RBR40 - RBS20 Wired Backhaul Inquiry

I’ve got a question in terms of using satellites to connect through a wired backhaul to my router.

Currently I have my RBR40 connected to the ISP’s modem, then have an wired backhaul Ethernet that connects my RBR40 to the 1 of 3 RBS20s.

The other 2 satellites are then wirelessly connected to the first satellite.

Can I use the other Ethernet port on the first RBS20 to connect to my PC and use it as a normal wired connection?

I.e. If I’m using one slot for a wired backhaul then can the other slot still be used as a normal Ethernet connection?

I had been doing so successfully for quite a while but then randomly recently have had my entire connection (especially to 2 additional satellites that connect to the first RBS20) upstairs trip up every once in a while and I’m not sure if it’s related.

Thanks in advance!