Questions about optimal settings for an Asus AX88U router

[Gigabyte16384]

Generally speaking, looking for what is currently considered the optimal (As in the best balance between stability and performance) for an Asus AX88U running the latest Merlin firmware. I've been fiddling with this thing for months now and I keep getting this feeling that I'm doing something wrong.

If it helps, we live in an apartment complex and there are about 17 wireless devices that are N, AC, and AX spread across the 2.4 and 5GHz bands with 5 wired devices being primarily gigabit. It’s an Xfinity/Comcast internet with 400 Down/10 up.
There's about 23 other routers visible from this spot if that helps at all. 16 of them appear to have strong signals from here. They don't appear to have their 2.4 and 5 GHz Access points separated, so realistically, it's probably that many on both bands.

In any case, we work, we watch movies, play games, do some weird things that pushes the network's ability to manage data quickly. Gamestream/remote play and Virtual Desktop/Air Link are very sensitive to the speed and stability of the network. Things start acting up and everything is pretty much unplayable until it recovers.
General usage is a mixture of things other than general web browsing. Gaming, streaming, remote desktop, Nvidia Gamestream/Steam Remote play, Virtual Desktop/Air Link, etc. Of course, there's also the usual video streaming stuff, but it's that weird latency sensitive things to worry about.
VPN would be a nice thing to have for stuff like running a Minecraft server, but that's a bonus feature compared to getting everything running as good as it can get for our network conditions.
Also, is Firewall: Drop IPv6 neighbour solicitation broadcasts still necessary with Comcast?

Any thoughts or suggestions for getting the best results from this router in these conditions?

 

[sbsnb]

Sounds like you might benefit from setting up QoS. The most important part is setting your upload/download speeds correctly. For QoS to function all the time or nearly all the time you have to set those speeds at about 90-95% of the slowest speeds you get after testing numerous times. Make sure you test at different times of the day and different days of the week. If you're on cable internet, focus on late afternoon and evenings when things tend to be slowest.

 

[L&LD]

Best Practice Update/Setup Router/AiMesh Node(s) 2021

The above link gives good suggestions on getting the fastest and most stable baseline settings correct.

After those have proven themselves to your satisfaction, change things slowly and cautiously (and one at a time) as (and if) needed.