Provided you’re not going to dedicate the machine to a singular task and imprison it in the closet, this might actually make a machine usable for you, all the way down to around 100Mhz. More here
First on the list and probably the most important, is to pick out a console font that makes your eye happy and uses screen space efficiently. Provided you have the framebuffer working on your computer (and if Debian can handle the framebuffer on this ancient, eccentric machine, it can probably handle yours too), I recommend something like the Terminus font. It’s strictly a matter of preference though.