MESH replacement options - XenWifi/Unifi/etc

[webreaper]

Hi all, this might overlap with some of the other threads, but looking for a higher-level opinion on an upgrade to my current network.

Current State:
I'm currently running an AC86U with two AC68Us as MESH nodes, all running Asus-Merlin.

• The AC86U is the main router and sits in the lounge, next to the modem.
• The AC68U in my office, which connects to the AC86U via a 2Gbps powerline link. This provides stronger wifi at the office end of the house, and also has an ethernet connection to my Synology NAS.
• The AC68U in my shed, which connects to the AC86U via a loooong ethernet backhaul, and provides wifi coverage for some of the garden

I have several wifi cameras around the property, mostly Reolink, connected to Synology Surveillance station. They're for a bit of security, but ostensibly as wildlife cameras in the garden. I run a VPN server on the AC68U for remote access (OVPN - but I'd really prefer to upgrade to Wireguard), and also a guest network; we have terrible cell coverage where I live, so everyone who visits needs to use it for wifi calling, internet etc. Probably got about 40 clients in total, ranging from Macbooks, to Phones, to various IoT devices.

I work from home 100% of the time, so need a reliable connection. We're pretty rural, so our internet connection is pretty rubbish - we only have FTTC, with 38 down, 7 up - and we're not on the Openreach FTTP built-out plan yet, so no prospect of significantly faster connection in the next couple of years. However, I'm finding the Asus getting more and more unreliable, with unexpected wifi drops, shaky connections. So I'm thinking that upgrading to something more modern might help with performance, coverage in the garden, and general reliability.

Options I'm considering:
I was looking at the Asus Zenwifi XT8, as it seems simple, and the 5ghz dedicated backhaul might mean I could ditch the Powerline in the house. However, I've read various stuff saying it has all sorts of problems, and some friends recommended I look at Ubiquiti Unifi, as it's more solid and bullet-proof. However, their range seems very broad and not entirely intuitive.... wondering if people can help. I think I want:

• UbiQuiti UX7 as the main router and network controller in the lounge
• Another AP in the office, to which I'd connect the NAS, and which would give stronger Wifi at that end of the house. Something like UbiQuiti U6-IW?
• Something like a U7 Outdoor or UAP-AC-M UniFi AC Outdoor Mesh - to give better wifi coverage across the garden for the cameras.

But... I'm not sure about the right combination of bits to buy. I don't really want to wall-mount the AP the office, so unsure if the Wall AP is the right thing to buy. Can somebody familiar with their product range direct me to what would work best together? Also, I gather you need some sort of Cloud Key manager or something, but I think that's built into the UX7 - but not really sure.

Are there any other systems I should look at? My main priorities are ease of setup, features (VPN + guest network etc), and reliability. I'd like to not have to power-cycle the routers on a regular basis.

Budget-wise: could go up to £750 for the whole setup if required, but would prefer to keep it cheaper than that.

Oh, and just to avoid going off at tangents:

• I'm not looking to put ethernet in for the lounge/office connection - my time and budget doesn't stretch to chasing cables into walls at the moment. So powerline is the best compromise. May hardware ethernet in future
• The garden cameras can't be hard-wired for various reasons, so must run through wifi.

Thanks for any help and advice that people can give!