I hope this doesn't come across badly but: NimForum is an open source project, as such I would encourage you or anyone to help improve its efficiency. I think there is a lot of low hanging fruit here and I'd happily help with any patches that fix them.

Back in 2018 when I implemented the basis for this modern reimplementation of the Nim forum I focused on the functionality and a solid CI so that we can easily accept others' contributions without fear of regressions. Unfortunately I had only 2 solid weeks to make this a reality and optimising the code size didn't make the cut.