Glad my feedback had value.
I struggled with this for over a year, going back and forth with Eero and Garmin Support. Neither would own a fix. I eventually landed on a workaround for my Eero network that has been reliable for me:
Setup the Eero's Guest Network and connect my Garmin to that.
This essentially bypasses the Advanced Security feature part of the Eero Secure+ paid security subscription, which I use. In my research, it is this, the Advanced Security feature, that prevents my Garmin device from connecting. Others have reported the same.
If you don't have a Secure+ subscription (or are not on the introductory trial), then you may be having a different issue.
It's also worth noting that sometimes you have to power cycle the Eero after making all the changes. Same with the Garmin devices. I've read people implementing these adjustments, and the workaround not taking immediately. So if it doesn't work right away, check you settings, reboot everything and try again.
I just tested my FR630 running all the latest updates, connected to my Guest Network, and it transferred without a hiccup!
In the midst of all the "FUN" to see how fat I am....my buddy is a Garmin marine electronics installer and service org, and he said not to discount how screwed up the Garmin Connect app is in controlling the devices, like the scale or the watches or the boat instruments which he says have the same "quality software" that you and I have encountered. He does not use WIFI for his watch or devices because of these issues.
I uninstalled Garmin Connect on my Samsung Android phone whihc he says is where the WIFI profiles for the devices are housed. I re-intalled it and then configed the scale user setting/wifi...........got my first two weights logged since June 17th.
I still think the v3.20 Scale software update is to blame........
So I am SURE the advanced spam features on the eeco are a contribut - strike 1 or, the scale updated software - strike 2. Garmin Connect as the bluetooth and wifi king pin and repsosityr for the device management software etc etc. - STRIKE 3!!!!!
I wish Tech support at Garmin ( my second call in over 5 years) was a little more useful and knowledgeable. BUT at least there is this online forum and folks like YOU are here.
For what it's worth, recently I couldn't get my watch to connect even to my Guest Network on my Eero. I don't know if the issue was a firmware update to the Garmin, or if it was on the Eero end. But I resolved it by removing my wireless networks on my Garmin through Garmin Express, syncing and adding them back in. I'd actually left my old primary SSID on the watch as it didn't seem to matter, but now I've taken it off all together.