Ignore model number given in the field, my model number wasn't in the dropdown. This is about TL-WA801N.

I am unsure about the settings to use when configuring the access point in client mode. I am using it to provide Wifi access (via an Ethernet cable) to Home Assistant running on a Raspberry Pi 4. The router is an Orbi.

I have set a static IP address on the Home Assistant instance, and this is set both in the Home Assistant settings and in the Orbi router settings. The gateway and the DNS server in Home Assistant are that of the Orbi router.

I have set a static IP address on the TP-Link access point, and this is set both in the access point settings and in the Orbi router settings.

This works. However Home Assistant constantly drops out and so I am wondering if I have done it right. Should I not have set a static IP address for the access point? Should the gateway and/or DNS server for Home Assistant be that of the access point? 

I am missing a basic understanding of how client mode works which is preventing me from working this out.