That wasn’t a black-and-white comment, though. If pros don’t want to put in the effort to get openHAB running in Docker/Windows/etc. (someone’s even running it on Android), they can still choose to use openHABian. It’s just that they have more “easy” options due to their expertise.
At this point, we’ve probably given you too much to think about. All you really need is a solid backup strategy, regardless of your storage type. An RPi4 is probably the easiest and least expensive “drop in and keep going” solution to replace your RPi2, but I can see the appeal of an RPi5.