If you are going with TP-Link equipment, choose the ones you can manage with the Omada controller.

ER605 that you decided on

TL-SG2210MP managed switch with PoE

EAP610 access point that is WIFI 6.

Then you would need the controller, that you can install on a PC or Pi, or you can get the OC200 hardware controller

This will enable you to control all the devices in a single web page.

If you happen to have coax in the house, consider using MoCA adapters to get wired connectivity for an Access Point (AP) at the remote location.

Here are some diagrams from GoCoax that show how to use MoCA.

An access point like the TP-Link EAP610 will work for this kind of a setup. Just need to configure the SSID to the same values as your base router.

Try the TP-Link EAP610s.

If you tried mesh and used wired backhaul you should have gotten good results.

You can look for an Access Point (AP) on Amazon or elsewhere to fill that need. An AP is essentially that component in your router that does the WiFi.

Here is the TP-Link EAP610 which does that, but it may not be the form factor you are looking for. There are many others. Many APs require PoE adapters since they have no native power supply to plug in, so be aware of that. Also look for one that is WiFi 6 (AX).