I'm the original author. There's one other that works on code, and Vert (this blog) has been a tremendous help with asset updates.
Turns out however that rewriting the graphical engine takes a while.
Ever considered open sourcing it? Pretty sure some people will contribute, it’s an iconic game
Considered, yes, but Uplink is not open source, and it's not my right to do it either. I know the source is generally "out there" but the legality of that is murky.
Have you tried reaching out to Chris DeLay and asking him about it? He might be okay with it!
Does Onlink use any of the Uplink source, or is it written entirely from scratch? If the latter, it's definitely within your rights to open-source.
Already said it to vert, but just wanted to say I wish you luck. Onlink was tapping into a niche that I think is super under explored and you clearly understood what was actually fun about it.