Which one to buy
Pick the shape first: an In-Wall goes where you already have a data jack and want wired ports in the room, and a Pro goes on the ceiling for whole-floor coverage.
Between generations, the U7 Pro is the one with a 6GHz radio and needs PoE+ at about 21W under load, while the U7 In-Wall is Wi-Fi 7 on 2.4 and 5GHz only but adds a 2.5GbE downstream port; the U6 Pro at about 13W is still a solid all-around ceiling AP for a larger home.
Wi-Fi design work (SSIDs, channels, RF profiles) happens in the UniFi controller on all four, not in Home Assistant.
I haven't run any of these; the picks are based on the spec sheets and what other Home Assistant users report.