Are there any third party services that don’t require phone numbers for sign-ups?
Try this: bore
For domain names, you can go with any reverse proxy like nginx proxy manager or caddy or anything else you like.
How do you access those services from a public network? Say, you want to access something while working from your office or a friend’s computer.
Sure, but what if that computer doesn’t have wireguard installed. I don’t see any other way except exposing the service to the public.