Satellite LAN bug fixed by August 2020?

I'm shopping for a mesh system and Orbi keeps winding up at the top of my list.  I could get a RBK23, or an RBK50 and think about adding an extra satellite later, ideally an RBS20.  (It would be difficult to buy an RBK53 kit in my location, and I can do wired backhaul for the second satellite so the extra antennas are not a big deal.)  I would be using the whole rig in AP mode for now, because my ISP does not offer standalone modems and their modem/router combo is supposed to support bridge mode "real soon now", for the last year :(

My question is, I've seen a number of older posts like this one that describe serious problems with LAN devices talking to each other, especially in "mixed" satellite configurations like an RBS20 connected to an RBR50, especially in AP mode.  LAN traffic is important to me -- I run a Plex server, and do a lot of in-home video game streaming.  I'd like to know if the issues in these older posts have been resolved through firmware updates, before I commit time and money to an Orbi setup.  (As far as I can tell, I can't reply to posts as old as that one, so I just have to hope superczar notices.)

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As an aside, I also see a lot of posts like this one about losing connectivity or general flakiness, that wind up being a "bad" firmware update.   It sounds like just letting the router auto-update is OK, and these problems are caused by manually applying an update just because it said a new one was available in the management page.  Is that correct?  I don't feel any need to apply updates just because they exist, but I do want to make sure that security holes get patched in a timely fashion -- did I understand correctly that security-relevant patches are applied with no user intervention?  (And that those security patches generally don't break basic functionality?)