Please suggest a setup - Amplifi vs Unifi vs other arrangement?

Hi Network gurus

I have been reading a lot about my options but would appreciate if you can give me some pointers to firm up my plans.

At the moment my setup goes like this:

Fibre -> ONT - > Huawei 659b -> Netcomm 200 mbps Powerline (all in garage at far end of house)

Netcomm 200 mbps Powerline -> TP-link router used as AP (the other end of the house) ...> TV

Most of the network activity is at the end of the house away from the garage and one level up and one level down. Problem is speed one level up and one level down; and coverage one level down.

I had to use Powerline as there was no easy way to run an ethernet cable between the Huawei and the TP-Link. However, I have been doing some investigations...

My recent findings:

The house has an underfloor crawl space from the garage a third of the way along the house. I have been crawling under the house whole morning and found that I could get an ethernet cable from the garage down there. I found that some of the telephone cables underfloor are actually Cat5E cables. I am thinking of repurposing the phone cable as we don't use landline (who does these days?). By doing that I can get ethernet to one of the phone jacks in the middle of the house (which is not accessible via the crawl space).

I am considering the following two options:

Option 1:

Fibre > ONT -> Huawei -> Ethernet cable (including a length of repurposed phone cat5e cable) -> Amplifi router (in the middle of the house)

Add One Mesh point upstairs and one mesh point downstairs

Potential Problem:

the TV will be streaming via wifi only. Not sure if this will be good enough.

My older Mac Pro and MacBook are 802.11n only. Connectivity to the Mac pro needs to be good for work (at the moment I have a third power line and runs an ethernet cable to it). Not sure if this option will actually make it worse.

Option 2:

Fibre -> ONT -> Huawei -> USG -> USW (in garage) -> Ethernet cable with POE

One Unifi AP in the middle of the house ground level (splicing a ethernet cable with an existing phone cable which is Cat5e)

One Unifi AP one level below (splicing a ethernet cable with an existing phone cable which is Cat5e)

Potential Problem:

Same as Option 1 but more expensive

Any other options I should consider?

Thank you in advance for any suggestions