Power line is no replacement for a decent wired or even 6GHz backhaul

I am confused. Assuming you are in Canada.

Is your “Current Scenario” in a different domicile from where the “Required Scenario” will be?

Is Rogers your current ISP and will still be in the new Townhouse?

If the ISP demark from Rogers is a Coax cable to the XB7 in the garage, simply use a F-type barrel connector to connect the incoming coax from Rogers to the coax cable running to the basement. Then relocate the Rogers supplied XB7 Gateway to the Basement. Then connect your mesh and Ethernet connected devices as norman.

Why do you need a MoCA splitter, when all your equipment lives in the basement? Why even mess with MoCA unless there is some other connectivity that I am missing.

Synology. And do not buy a 2-drive slot model. Go with either four or five drive capacity. You will be wanting to upgrade within the next four to six years.

https://www.synology.com/en-us/support/nas_selector

Then purchase on Amazon.

Utilize the ground connector on all of your IT equipment.

Every Ethernet connection needs --> https://www.amazon.com/dp/B07H5PWWQ1/?coliid=I2PEOQH58OLZRF&colid=27J18KZ6WBXEZ&ref_=lv_ov_lig_dp_it&th=1