I had similar hardware 15-20 years ago (my laptop was about the same specs, just maybe 16mb ram?) and I ran NetBSD 1.4.x on it. This was before pkgin so you had to use the ports collection and compile or use the fairly simple pkg_add system.

For web browsing I did dillo and links -g ... it worked on a lot of the internet which at the time still did not heavily rely on stylesheets and javascript for baseline functionality. For email reading I used one of the many terminal readers, I believe pine.

For instant messaging I used naim. Social networking through websites wasn't a thing yet nor was youtube. I used mpg123 to do music and I believe I ran in screen without X up most of the time.

Before that I had an IBM 360c (https://en.wikipedia.org/wiki/IBM_ThinkPad_360) with 8MB of ram. I used I believe NetBSD 1.2 on that. I could even recompile the kernel without hitting swap with some very interesting gcc flags that I have long forgotten - but it still took I believe most of a day (maybe 7 hours?).

NetBSD 1.6 was really where the split began ... the priorities were different and things seemed slower. It is mostly meant for academics and research so this ultimately makes sense.

It's like a lifetime ago.

So when I got this up and running, NetBSD was exactly what I turned to. It's different of course now. But the P90 is surprisingly able to reasonably keep up as long as you have patience and modest expectations.