Experts, help me hard wire a more reliable connection to my MR/MS80 mesh system for my home office.

Thank you everyone, really appreciate all the useful help and it's solved! 🎉 (1) Yes, the old Actiontec MoCA adapter was a subpar companion to the goCOAX adapter. Happily, I found my second goCOAX, so have the same brand/model on each end of the coax. No splitters involved. (2) It helped to get an ethernet adapter for my laptop that actually worked, to check things. 🙄 I found this out while making sure the adapters were working. Fortunately, we had another lying around. (3) Once I confirmed that I had internet through the MoCA, I chose to set up my extra MR80 router in AP mode on the same network and unplugged the existing daisy-chained studio satellite. If I ever run into interference issues, I'll backhaul the satellite instead or, worst case, use MoCA as a dedicated ethernet connection but, who knows, maybe I can go nuts and put the satellite in the tool shed, even further back in the yard. — Thank you, again, for the quick and helpful responses.