I have the same problem where most of my smart home devices using wifi is disconnected from eero 6e randomly. Either of restarting a smart device reconnects or restarting eero itself make smart devices re-connect.

Here is list of smart home devices that are having the disconnection problem.( # of disconnections for last 14 days)

1. Google Nest Hub Max ( 3 times )

2. Switchbot Hub Plus ( > 7 times)

3. Netatmo Weather Station ( 3 times )

4. Fire TV Cube gen 3 ( 2 times )

5. Teckin smart plug ( 3 times )

6. Coway airmega 250s ( 3 times, auto-sleep )

7. Canon imageCLASS MF642Cdw ( 1 time, auto-sleep )

 

My findings are

- #2, #3, #5 are sometimes disconnected at around same time between 9~10am. #2 is more frequently. 

- The devices that have auto-sleep feature are having less # of perceived disconnection(because sleep technically disconnects wifi and wake re-connects)

- I turned off all features in lab and reserve ip addresses for those devices. but none of them helps

- my eero 6e have had updates for multiple times for last 14 days. so, there can be multiple disconnections that I didn't perceive and were fixed by restarting after firmware update.

- Devices requiring continuous wifi connection are having more # of disconnection problems. so, I couldn't notice this problem with laptop with 2.4 since I don't use it for 24 hours.

- AFAIK, it is eero's limitation where 2.4 and 5 cannot be split. 

 

In conclusion, I guess it is hardware limitation and people like me who has lots of smart home devices using 2.4 should have a different router.