I get it. A new firmware branch is a big deal. I have no idea how Asus handles that internally. I used to support a software control system and my spouse runs a software control system for a living. So I know that changes can be applied from one branch to another, if you have a capable system...
I just want the thing to work well. I don't know that expecting significant new features to be added after over 3 years is realistic. And calling that a product end of life if those features aren't likely to materialize seems questionable to me.
Earlier I enabled UPnP on my AX86U with latest stock firmware and tested with Shields Up which reported "THE EQUIPMENT AT THE TARGET IP ADDRESS DID NOT RESPOND TO OUR UPnP PROBES!" I normally keep UPnP turned off out of an abundance of caution.
I have UPnP disabled and can't really change it to test it right now but I'll try it later when I can.
Update: I enabled UPnP on my AX86U with latest stock firmware and tested with Shields Up which reported "THE EQUIPMENT AT THE TARGET IP ADDRESS DID NOT RESPOND TO OUR UPnP PROBES!"
The 2.4GHz coverage was already pretty good when I bought my AX86U, but the 5GHz coverage was a lot better. The AX86U is the first router I've owned that provided decent 5GHz coverage of my entire home.
If I was buying today and the price was similar I'd strongly consider the pro model. I bought my RT-AX86U approximately a year and 5 months ago. It's been a good router and I'm not overly concerned about losing firmware updates as Asus has been good in that regard, in my history buying their...
I've never had my RT-AX86 update when auto update was disabled. But I do think that one firmware update did turn auto update back on. Just once. I go check for updates fairly often so I noticed it and turned it back off.