Still connection loses and buffer overflows

In the meantime I've almost got used to the fact that the WiFi disappears for a few minutes every evening, only to return after what feels like an eternity.

The fact that I reset the devices to the factory settings every few weeks in order to set them up completely again became routine.
I always do this when the first of my “2.4 GHz only” devices no longer receive an IP address, a sure sign that my WLAN is about to fail completely.
A software bug from my point of view, but apparently I'm the only one watching this behavior. Now I have around 60 participants in my network and around 45-50 of them are connected via WLAN (since they cannot do anything else).

NETGEAR always sounds big enough to turn to if you see bugs, but apparently those bugs are not being resolved consistently.

But what I have to say, none of my other WLAN systems to date has been as powerful and reliable (apart from the effects described above) as the ORBI 853. I had already used three other manufacturers before and all of them were not enough for my requirements, the vast majority of them break in performance after 30 Wi-Fi devices and that is quite a crap. According to the prospectus, everyone is talking about up to 200 devices, but unfortunately that's a lie.

I would be happy to receive real tips regarding the mistakes I have described above, but I don't need good advice, I have so many of them that it lasts to the end.