It's a tedious, manual process, but I have used https://fontstruct.com/ to make TTF fonts from bitmap fonts before.

There was a post just recently on this topic: https://news.ycombinator.com/item?id=23129434

If the Fontstruct thing is better or easier, the author might benefit from a pointer to it.

Also it was mentioned that the https://int10h.org site has its own article on the method they used, but I can't find the link now.

Every time old fonts come up, I have to mention Cool Retro Term:

Sorry for the music in this video, but cool-retro-term really is a thing of beauty: