Deco Mesh Ethernet and Wifi Backhaul

Good day!

I am planning for a setup for a 3 story house.
I am new to the DECO mesh system and would like to confirm if this setup will work or if there are better ways I can configure this setup.

What I have?

• 3 DECO x50s.
• TP Link Gigabit Router
• Modem from the ISP.

Connection:
1. Fiber from drop point to ISP provided Wifi 6 modem.

2. Dedicated Ethernet port connection between 1st and 3rd floor.

Plan A:

1. Connect Main Deco to ISP Modem at the 1st floor.

2. Connect 3rd floor satellite Deco to Main Deco via Ethernet Backhaul.

3. Place a satellite Deco on the 2nd floor and let the system decide which Wifi Backhaul it can connect to either 3rd Floor Satellite or 1st Floor Main Deco.

Plan B:

1. Connect TP Link router to ISM Modem at the 1st floor.

2. Connect 2 Deco to routers as APs. This is for 1st and 3rd floors.

3. Place a satellite Deco on the 2nd floor and let the system decide which Wifi Backhaul it can connect to either 3rd Floor Satellite or 1st Floor Main Deco.

I would like to confirm if these topology are possible with the devices I have.
I would like to know which Plan (A or B) is better or if there are other possible topology.

I would like to confirm if DECO in AP mode will still have the "smart AI driven" mesh feature with seamless transfers between the decos.

Thank you very much for your help.