And they are promptly out of stock, I assume. I've owned every Raspberry Pi since the first one but I think the 4 was my last one. They are fun to tinker with with but not great for long-term use in my experience. I felt like I had to babysit it way too often, it absolutely wasn't a "setup an forgot" device, again in my experience. It'd be rock solid for 2-3 months then randomly stop working, rinse and repeat. A litt…
I have Pis that have been running for 3+ years now (and that haven't been running longer because I upgraded them to Pi 3 or 4 boards, although they are performing the same jobs), and it's not just the OS either - I have Raspbian on the Pi 3 that runs my desktop touchscreen monitor (which controls all my lighting, and has an uptime of 167 days), and Ubuntu on my Homebridge/Zigbee gateway (which has an uptime of 61 days because I upgraded it before Summer, but has been running for nearly 2 years now).
If you need more CPU power, the RK3588 boards (as long as they have proper Armbian support) are decent bets, but at that point an Intel N100 might be more interesting since those CPUs can average below 10W on light load and will boost to better overall performance. Yes, they will be more expensive, but the going rate is 16GB RAM and 512GB SSD for less than $200, so...
But if you want something that just works _forever_ at under 5W mean load, the Pi 4 is still it. And you can boot it off an USB SSD to great effect (I have a Proxmox instance running that way).