Linksys - WRT1900AC

I can’t speak to the wireless performance since I use Unifi for that, but my WRT1900AC has no problems with gigabit internet and can even SQM up to about 600Mbps.

No, I already knew this. WPA3 and MU-MIMO are not working on 8964 I own both WRT1900ACv2 and WRT3200ACM, the 1900ACv2 uses different WiFi chip and it has slightly better support than the 8964, even with this the 5GHz WiFi is still not very stable (I use it in office now and it has short interruption many times in a day)

Well, timing might not be accurate, but no matter how many commit there were, does any of them ever bring back the "MU-MIMO" back? Most of them are just bug fixes to existing thing. The driver was abandoned by NXP since the day of acquisition, this is a known fact, the community could hardly make any feature improvement on WRT series, the WRT1200/1900 series also didn't get much break through until recent 1-2 yrs (that's why now I am using my WRT1900ACv2 but not WRT3200ACM) I don't know why you keep sticking on the "almost a decade" thing, it's not helping at least OP to recognize the fact that the WiFi on WRT3200ACM is bad.

Networking equipment should not be BIFL. Technology changes and gets better. Just because something CAN work doesn't mean you should still use it. My old Linksys WRT router was awesome, but it could never go faster than 54mbps on wireless. Later devices were faster, but struggled with more than a few wireless devices. My old router would max out at 10 devices and then pretty much self destruct. My current stuff can handle hundreds of devices, but I have access points that are gen 5 and can't do the faster speeds. Even now, I'm wishing I had 2.5gb or 10gb ethernet capabilities, and if I could actually come up with a practical use case where 2.5 or 10gb would make my life better, I would drop $200-400 on a new switch to allow me to upgrade.

Rule of thumb I tell customers is you can usually troubleshoot issues if it’s younger than 5 years. 5 years and beyond if you have trouble you can put a bandaid on it but start making plans to replace it. My favorite thing is when customers call and they’ve got N150s / WRTs / etc like “WHY AM I NOT GETTING MY SPEEDS”, no fucking kidding you aren’t