I think that the 5. GHz signal would be too weak. Is it also possible to create a 2.4 GHz mesh?

Signal strength is around -78 for 5.8 GHz and -65 for 2.4 GHz. I checked this with my phone. Not sure if the 610 antennas could improve that.

I'm trying to improve WiFi coverage in my basement. I'm living in a rented flat on the second floor. There are currently two EAP 610 in my flat mounted to the ceiling which provide a very weak signal...