Hi Zachary,
"Mechvibes and Klack [...] both have some shortcomings: [...] large, [...], lags, [...] closed-source "
Did you check out Bucklespring? Tiny (15kb binary), open source, runs on linux, macos and windows:
https://github.com/zevv/bucklespring
on Debian or Ubuntu just "apt install bucklespring" and you're good to go.