Sorry in advance for the long post

I'm looking for some advice on how to build out my Unifi network while future proofing it but also not going over the top (possibly asking in the wrong forum I know)

About 12 months ago I started the process of replacing my existing networking equipment with Unifi gear. First step was to get structured cabling and a rack installed and then replace my router and switch with a UDM SE. I pretty quickly maxed out available ports on the UDM and have added a couple of flex mini's around the house as temporary measures so I will need to add another central switch into the rack.

I'd also like to replace my current wifi APs with unifi ones. I currently have an old Apple Airprot Time Capsule and Airport Express at either end of my house. I've also added a Unifi AC Mesh in my garage areas that broadcasts an IOT SSID for devices outside and at its end of the house while other IOT devices are on my main SSID for now. There's currently about 50 devices on wifi all up but that will probably grow on the IOT side of things

Third on my list are some Unifi cameras for outside and a Doorbell. I had the cabling installed for 4 of them last year but they are lower priority than the switch and APs.

Questions

• What line of switches should I be looking at? I'd like to take advantage of the SFP uplink from the UDM SE. Some POE ports will probably be useful for future but my thinking is to move most connections from the UDM to the switch except anything requiring POE. I've only got 3 devices powered from the UDM but adding cameras will only give me 1 extra poe port for future. I also currently have 22 ports wired around the house and while they're not all patched currently I'd like to have the ability to at least patch them into a switch

• I had assumed I'd jump to one of the 7 series APs but have seen a lot of issues with IOT devices and not sure if I should hold off. Also don't really want something that will have an audible fan in it that will potentially annoy the other half

• Given how old my existing APs are and that they're bookshelf style units and not ceiling mounted should I look to replace them with 1 or 2 Unifi APs? We've found we've got some areas where the signal struggles to get through walls/appliances e.g. one AP is on the backside of one wall in the kitchen and the signal struggles to make it through to the room on the opposite side. Would newer ceiling mounted units have better transmission capability and overcome these issues? Is there a way I can check before I buy or should I just buy 1 and try placement options?

Sorry for all the questions. I'm trying to get my shopping list sorted so I can take advantage of any black Friday/Christmas sales this year to get what I need without spending an arm and a leg