My impression is this is gradually going by the wayside for all brands, and that's not just on the manufacturer support side but also the breadth of custom roms available to different brands/models. The exception is if you get a Pixel which has 'top tier' support for custom roms and then there's a sharp falloff. Past that point you're into "your mileage may vary" territory with how much feature support is retained or degraded by the rom, and if you're bothered if banking apps require a phone with play integrity or playing hide and seek to pretend it's unaltered.
This is likely just my perspective, but it seems that there's less to be gained from custom roms in recent years anyway as smartphones have matured and the rated of change has slowed. Plus there has been a trend among some brands to offer longer OS support lifecycles, of which Samsung seems to be one of the best for android.
OnePlus used to be the king for custom roms, then they just completely abandoned allowing them. Even if the community was small, I really do think the halo effect of the power users attracted to their brand was more important than they gave credit to it, which is why I think they are not doing so well anymore.
You can still remove all the Samsung crap, install your favorite launcher, and use Fdroid. This is what I do and couldn't be happier with a debloated Note.
Only in the US it seems. Non-US models usually have no issue with bootloader unlocking and the custom ROM scene is usually pretty active.
It may trip an e-fuse though, causing some features to be disabled forever. But unfortunately that's the direction Android has taken over the years. Getting stuff like banking to work on a non-stock phone is getting more and more annoying, even for the most hacker-friendly phones. I have stopped with custom ROMs, too much hassle for a daily driver, smartphones are not fun anymore, they are more like appliances than general purpose computers.
I left Android for Apple precisely because I could not stop myself from playing with custom ROMs. I had too many better things to do with my life. Android was fine, but iOS is less distracting.
