"I installed version X.Y.Z and so far so good"
"I tried all available updates and it keeps crashing".
There is no transparency in the published updates. Take that firmware blob (which is probably 99% GPL licensed by the way) and shut up. That's basically what the vendors are saying.
What's ironic is that most OEM are using some sort of out of date openwrt derivatives as a base for their closed source firmwares, which are obvious GPL violations.
Do you have a source of that or am I out of date? Based on my knowledge, outdated, GPL-violation OpenWRT would still be a massive upgrade over what's usually developed in-house by OEMs.
Musk's "Starlink" router is also OpenWRT based
Buying $30-$40 access points on eBay is a bit of a hobby of mine. I've been using a Netgear R8000 as an access point for a few months. There's no OpenWRT support, but it's supported by FreshTomato. Qualitatively, it seems to work well in terms of latency and throughput when the signal is strong. It seems to perform worse than the WRT1200AC that I was previously using at that location, when at the fringe. When I'm at the center of my house, my phone tends to associate with it but then struggle to get packets through. Maybe I just need to dial down the AP's TX power, though.
These system are almost always built on the official SDK provided by Qualcomm, known as QSDK.
QSDK is a fork of an old OpenWRT version (chaos calmer, 2018). Unlike the open source version, it includes proprietary drivers and many changes. Openwrt devs refer to it as a "frankenfirmware".