Topology is simple as: Internet--- Router---T1500G---EAPs, I think this should be ok if you have no special requirement, no need for TL-R480T+. Besides, you can share with us that do you have any...

It's plug and play as an unmanaged switch. So you don't need and have no way to configure the QoS function on SG108. The QoS rules are already set in the switch and can't be modified.

No, Easy smart switch doesn't support remote management.

If you got an EU version unit, there is no way to set the transmit power higher than 20dBm... While I am curious why you have got an EU version unit since you are in US, where did you buy this unit?

Has your problem been solved?

Suggest you to do a spectrum analyze on 5GHz, at the mean time, please select a cleaner channel on EAP245. Besides, for the configuration of EAP245, you need set its Tx power as high level, and then...