After the (temporary) defederation announcement of earlier i checked the Lemmy repo to see if there was already a ticket on the federation limiting option like Mastodon's that people mentioned Lemmy doesn't yet have. Not only i didn't find it, i also saw that there's about 200+ open tickets of variable importance. Also saw that it's maintained mostly by the two main devs, the difference in commits between them and even the next contributors is vast. This is normal and in other circumstances it'd grow organically, but considering the huge influx of users lately, which will likely take months to slow down, they just don't have the same time to invest on this, and many things risk being neglected.
I'm a sysadmin, haven't coded anything big in at least a decade and a half beyond small helper scripts in Bash or Python, and haven't ever touched Rust, so can't help there, but maybe some of you Rust aficionados can give some time to help essentially all of Lemmy.
The same can be said of Kbin of course, although that's PHP, and there is exacerbated by it being just the single dev.
The ones listed are the ones with write access as far as I'm concerned. The others just work with pull requests. You can go try see for yourself. No matter though, of course more developers is desirable, but my takeaway is that it isn't as serious as OP makes it out to be
If a commit is brought in via PRs, they will be listed as contributors. It is at 153 contributors with 2 main ones. Not too shabby.