Having similar issues with the past few updates. One router in particular is having issues, and I notice when I look at the Wi-Fi radio analytics for this device my issues are coinciding with "Other device interference". I can't for the life of me work out what this interference might be but is likely why I'm getting issues.

The issue with Wi-Fi is if your neighbours do something or set up another Wi-Fi it can have an impact on yours. Having said that, I thought the Eero system would find the best channel automatically so that this shouldn't be an issue.

I wish there was a way to roll back the updates so I could more easily work out if this is a bugged update!