Searching around, I found someone that benchmarked gobgp, rustybgp, and some others, and gobgp didn't seem to do all that well compared to other implementations.
rustybgp seems to do pretty well (see #5 post of blog series) and is created by the same author(s) of gobgp. Additionally, it looks like the configs are transferable between gobgp and rustybgp.
https://elegantnetwork.github.io/posts/comparing-open-source...