For the last few weeks I have been troubleshooting the stability of my Local Area Network. 95% of the time, it works fine. The other 5% I will experience stuttering/lag if I stream something across the LAN (video, game, or remote desktop).  I believe this is also associated with slow-feeling web browsing.

The server on the LAN is a Windows 10 PC connected via ethernet to the router.

A typical use case will be streaming a game from the PC to my Steam Link device on my TV, which is connected via 5ghz wifi (in the same room as the router, with clear line of site about 25 feet away). I will notice some abrupt lag, and pinging the PC or the router during this time will show very bad results.

For example:

Pinging the router:

64 bytes from 192.168.0.1: icmp_seq=3 ttl=64 time=2.901 ms
64 bytes from 192.168.0.1: icmp_seq=4 ttl=64 time=4.336 ms
Request timeout for icmp_seq 5
Request timeout for icmp_seq 6
64 bytes from 192.168.0.1: icmp_seq=6 ttl=64 time=1350.986 ms
64 bytes from 192.168.0.1: icmp_seq=7 ttl=64 time=347.453 ms
64 bytes from 192.168.0.1: icmp_seq=8 ttl=64 time=7.013 ms

Or pinging the PC from my laptop:

64 bytes from 192.168.1.108: icmp_seq=5 ttl=128 time=10.918 ms
64 bytes from 192.168.1.108: icmp_seq=6 ttl=128 time=49.491 ms
64 bytes from 192.168.1.108: icmp_seq=7 ttl=128 time=59.175 ms
64 bytes from 192.168.1.108: icmp_seq=8 ttl=128 time=202.339 ms
Request timeout for icmp_seq 9
64 bytes from 192.168.1.108: icmp_seq=10 ttl=128 time=30.333 ms
64 bytes from 192.168.1.108: icmp_seq=11 ttl=128 time=52.461 ms
64 bytes from 192.168.1.108: icmp_seq=12 ttl=128 time=151.771 ms
64 bytes from 192.168.1.108: icmp_seq=13 ttl=128 time=446.120 ms
64 bytes from 192.168.1.108: icmp_seq=14 ttl=128 time=165.935 ms
64 bytes from 192.168.1.108: icmp_seq=15 ttl=128 time=86.602 ms
64 bytes from 192.168.1.108: icmp_seq=16 ttl=128 time=129.742 ms
64 bytes from 192.168.1.108: icmp_seq=17 ttl=128 time=25.671 ms
64 bytes from 192.168.1.108: icmp_seq=18 ttl=128 time=15.458 ms
64 bytes from 192.168.1.108: icmp_seq=19 ttl=128 time=4.364 ms

During normal-feeling operation, pings to the router or the PC are in the <20ms range is low variance. The laptop is in the same room as the router. I live in a fairly sparse suburban area so the wireless environment should be relatively healthy.

I've tried changing the wireless channels and channel widths, power cycling the router, enabling OFDMA, disabling Smart Connect, and enable Zero Wait DFS.

Even as a type this and work on the router's web UI, things are noticeably slow to load.