Are you sure it is the eeros? I have 3 in my house and they do not constantly change channels. Mine use channel 1 for 2.4G and have never moved to another channel. I do understand your frustration with crowded bands but am not sure it is your eero neighbors fault.
Yes, it was the eero. I watched the eero change channels over 10+ times during a 10 minute period. Many times overlapping with my 2.4 ghz channel and the signal being almost the same as the asus repeaters i have in my house. During this time, the latency for my 2.4 ghz wireless went up to 100ms+ at times and every 2 out of 10 packets dropped. It looks like the eero has settled down now. Maybe the neighbor was moving them around or resetting them, don't know.
During that same time, some odd dns resolution issues as well, couldn't resolve dns consistently on 2.4ghz. I could ping cloudflare pretty consistenly, but could not get to google.
There are also a few hidden ssids radio hopping as well. For the few that i tracked down, they are amazon firesticks. I don't know where amazon decided not to use valid mac addresses for the hidden wireless ssid they broadcast. Two of my three firetv boxes are wired in using asus repeaters with ac for backhaul, but the remotes still use wifi of sorts.
Another thought, at this point with the density of 2.4ghz radios in the area, i think any change to the topology kicks off some of the routers to change channels due to auto channel setup. This then causes a cascade of devices hunting for a better channel.
For the most part, I stabilized my 2.4 ghz by disabling auto channel around 9 months ago. It was a little difficult at first since the the wireless menu on the asus routers are hidden after you enable repeater mode.
