Building the mouse Logitech won't make

I like my Anywhere MX 3.

The smaller size is actually ideal for my fingertip grip, and I actually like the rechargeable battery. It lasts well over a month on a single charge and then charges really quickly (if it ever does go flat, just chuck it on the charger while you make a coffee, 2-3 min is enough to last the rest of the day). And I love the scroll wheel.

The microswitches going bad is a massive downside.

I read somewhere that it's caused by static build up due to Logitech using much lower voltage/current than what the switches were originally designed for... After a bit of experimentation, I found that simply breathing warm air into the side of the left button clears up my issues for a few days....

Which is stupid annoying workaround, but what else am I going to do, buy a second one which probably has the same flaw?

My main workflow mouse has been the Logitech g600 for years. I love having 24 different macro keys accessible with my thumb (stuff like copy/paste, ctrl+w, ctrl+shift+t, enter, etc), but it's terribly un-ergonomic and the software is terrible (and doesn't let you configure settings except through its eye-watering UI). And afaict, Logitech actually stopped making them, so I have to snap them up whenever resellers put one on Amazon, since the main mouse button switch has a nasty habit of starting to double click after too long.

It's to the point where I'm considering just commissioning a hardware hacker to make me a custom mouse.

I, too, prefer disposables, but for a somewhat different reason. One very commonly used surgical item is a sterile suction/irrigator. It's sealed with 8 AA's at the factory, used for 2-3 minutes during laparoscopic surgery, and disposed of. So pretty much anyone who works in a surgical suite that does laparoscopy has a personally unlimited supply of AA's that would be thrown away anyway.

I found that wired trackballs with scrollwheels no longer seem to exist. I bought a wired trackball without a scrollwheel and absolutely hate it.

My chosen mouse (for now) is logitech G305 with silent switches swapped in. I've one with Huano (brown case, bright dot) and one with Kailh (the grey cube with big round, red dot). They feel different, both will be weird if you're used to stock, clicky omrons. I've also replaced the side switches, scroll switch and DPI switch (6 in total).

Kailhs have a sharper click feel, travel is smaller than stock. Huanos feel like they have more travel than stock, with a very long (soft?) tactile bump. Kailhs are marginally quieter. I don't prefer either, both are so much nicer than stock. I highly recommend swapping mouse switches, the stock omrons that logitech (and others) put in are loud, rattly trash. Huano makes really good clicky switches too. The good thing is that you can upgrade (fix) after the inevitable death (more likely double clicking than not clicking at all) of the stock ones. You'll likely want to buy both, because you will need (at least for G305) a square footprint switch to put under the scroll wheel. Kailhs despite being square and 2 pin, work fine for the main switches that have a 3 pin footprint. The third pin doesn't do anything.

I've not experimented with nor researched the scroll encoder yet. Maybe there are quiet options to swap in. It's not bad as is, but it'd like something quieter with softer jumps.

Except the obvious tools for soldering, don't forget to buy a new set of skates, because the screws will be under them. If the mouse is new, you might be able to unstick them intact. If it's not, you'll likely bend them and it won't glide as good.

About the mouse - I just like the shape of G305, the wireless is good and with a lithium battery it is pretty light and lasts a long time.

Lithium cells are like 7x the price, last maybe 2-3x as long, but are like 7-10g lighter, for mice get them only for weight reduction or working in cold places. People say Energizer ultimate lithium are the best, in my experience they last longer than lithium cells from Varta.