Yeah I think the 40s series is the sweet spot for nearfield, definitely.
I am not a subwoofer guy, in fact I am pretty much against subs. In my experience, the result never really match the theory. Bass frequency are not directional but if the speaker producing them isn't setup physically at the same location as the other speakers you get phase coherence and power mismatch problems.
On top of that most peoples do not have access to speakers that can produce such low frequencies, so it is not really worthwhile to use them to produce. You end up with results that don't sound that well in most systems because they lack a part of the work.
Sub frequencies are also felt physically and quite tiring for long term listening. It always feels nice at first, because it's suprising and powefull but really it is not where the focus in music production should be.
I have had access to some recording studios (even built a small one with friends in association) and my experience is they don't really use subs. If they need more power they just get bigger speakers that will reproduce the relevant frequencies coherently.
There is basically no instrument that goes below 20Hz, even a pipe organ which is a massive object basically requiring a church, does not get there. The energy requirement to produce sub 20Hz sound just doens't make sense and it doesn't add much to the music, you just feel a rumble, most people cannot even hear that low.
In fact even between 20 and 30Hz is not that important. It still requires a lot of power and either you get something that is dominated by the rest of you put the power and it covers everything else.
I played french horn in various harmonies and the tubas were right behind me. It's one of the few instrument that can technically hit sub 30Hz while still being of manageable size. Whenever they had a low part, their sound was much more quiet, the wind volume requirement to sustain those notes is tremendous and I can tell you there was not many compositions that would go that low, because composers know that.
Even if you want to focus solely on modern music, sub notes are just a gimmick, because like I said, they become tiring and overpowering really fast. I had a friend who was listening to dub constantly and over time it was boring, monotonous and tiring because of the omnipresent bass part. This genre is linked to the creation of massive sound system that tries to produce bass as low a possible for the physical factor but past the wow factor, it's not really pleasant and very likely to damage your ears if they play them over the 90db level.
So yeah Genelec sub are overpriced but this is not really a problem confined to Genelec. Every sub is overpriced for the benefits they have. It is mostly about dick measuring contest or being able to say we have the best and can produce frequencies most people don't care about.
Unless you trully have an end game monitor what you really want is just a better monitor that can produce the really usefull frequency range with more power without distorting while keeping everything in phase.
The biggest main monitor from Genelec (1236A), technically goes as low as 17,5Hz and this is what you really want, but in practice it's no even really needed.
There is a recording studio in my town, that got built by some friends and they produce music for Netflix. It's not a small studio size wize, the main room is big enough to handle a mid-sized orchestra (it was a disaffected cinema, they built around this to be able to work with projected movies), it's 1200m2 main room with 50m2 control room.
But they don't have subs. They have multiple mains, some are Neuman, some are older Genelec models and some are Adams for 5.1 handling (I think they technically have Atmos capacity since they have overhead speakers but they don't use it, it was too much trouble for little commercial benefits).
You can check it out there: https://www.instagram.com/studiospalace/
If you think you need a sub but don't have the biggest speakers your room can handle, you are misallocating money. They are just the cherry on top when everything else is near perfect. Like the cherry, they can add a subtle touch but not really necessary for good music production or even good listening. The quantity of music that will make use of them meaningfully is so vanishingly small it's not very relevant. It's like looking at cars and choosing solely on the top end speed, you are unlikely to need it and even if you want to use the capacity, the risks are not worth the reward.
This is why GLM doesn't handle multi-sub well, it's just not a feature that would get used a lot by their high-end customers, they can already pay for the high end monitors. And generally GLM isn't really the best for room correction but it is just a convenient solution that will work well with no hassle if you only buy hardware from Genelec.
I see Genelec as the Apple of monitors. If you have the money, it is hard to find a setup that will get results as good without spending a lot of time building a custom solution that can use speakers from mismatched brands. Just like you can buy hardware cheaper than Apple but it will require a lot of work to end up with a solution that is transparently integrated as well.
What is legendary about Genelec is not just their reliability (most monitors are perfectly reliable if you treat them well, unless you go for bottom of the barel made in China) but the quality of their frequency reproduction (especially if you consider size for the nearfields).
There are a few competitors that make comparable speakers (like Neumann, ATC or JBL pro line) but they are not necesseraly cheaper and don't really have a integrated solution like GLM.
In the nearfield range, Neumann does quite well but they are not as good as coax Genelecs, but they are cheaper.
I don't want to brag too much, but when I was in music theory while young, I always got very close to perfect score in music dictation. I have listenned to quite a lot of monitors from the most reputable brands (Genelec, Neumann, Dynaudio, Focal, JBL, Adams, KRK) or even less reputable brands (Presonus, Yamaha, Tannoy, Monkey Banana, Mackie, Behringer, Prodipe, etc) and my experience is that Genelec is up there in the quality of reproduction which is why they can commend such a high price.
I actually wish someone could come up with monitors that would match Genelecs but at a much lower price. So far, every niche maker that I have heard about only came close and weren't any cheaper (often more expensive actually).
In that sense, it's a lot like Apple laptops, the brands who come close to the quality are not doing it for much cheaper if at all...