UniFi is a reasonably-priced nice system that works well enough. We have ~3 UniFi AP's deployed around the church property, with a (password protected) guest wi-fi network set up for users to access.
During special events (e.g. our mini-nextgen/NTE training event we host) I set up an additional separate guest Wi-Fi network for visitors.
TIP: Generate Wifi QR codes easily using this tool: https://wificard.io/
TIP: Ethernet over Powerline does work. I bought 2x pairs 'used condition' (from ebay for like $35) and they work fine. Good save for our old Anglican building situation.