I don't have any good links. There has been an AMA with the developers earlier this year (on lemmy.ml) and I asked some questions regarding the development process and the direction of the project (and finances). I don't have the link available, since I switched instances in the meantime.
And I followed the Github issues for some time. Usually you get an idea about how developers handle things by looking at their interaction with the community. There are some requests from last summer which I think would be worth looking into, but the devs say they don't have the manpower. Same applies to several UI bugs. They're still pretty much untouched as development focuses on the backend. And I've heard from people that the maintainers aren't always happy with contributions. Which I think isn't great because if you have an open source project along with a community, and then people try to engage but get disappointed because their day worth of coding is wasted and the PR denied... That isn't going to foster a healthy community. I'm not sure if they're working towards a different vision of the project, or manpower is that scarce. I mean they have 2 or 3 people working fulltime on Lemmy and they get paid a salary. I think we discussed that in the AMA. They definitely don't get rich and pay isn't what a big company would pay.
And there was something with the instance admins that needs improvement. I'm not sure what that was. Either image moderation or resource usage. (Or both.) Because admins need to abide by the law and pay attention to what's uploaded (ideally without messing with the database manually) and I think they did some database performance improvements in the last few releases. I'm not sure. Rust should be fairly efficient. With databases you need to pay attention to what you're doing. But I don't know all the used frameworks. I'm just speculating here.
So... I really don't have a link. I just occasionally read what people post here and want. And I sometimes follow the development.
And the fediverse as a whole... I don't think ActivityPub is very efficient. The polling and simple design is compelling, but it's not very performant. And it has some issues with caching etc. Also people want extensions and functionality that is well-defined and interoperable. But AP is just a well-defined core. And I think not even voting is part of that standard and just something people kind of agreed on. Which is problematic. Lots of normal stuff in Mastodon, Lemmy, etc isn't really part of the standard. And I'm not sure if they release a new revision at some point. I think the current revision is a bit older as of now. I think we need that because the whole Fediverse is about interoperability.