Tailscale is free for 3 users and up to 100 devices, so it's a fine solution vs running your own VM for hole punching. Consider your time value. You can even pay for Mullvad exit node access for devices in your net and configure the coordination layer accordingly.
Free was the price, client didn't want to pony up for any additional monthly fees. In the past I would've included it into my monthly "on call fee" but now I value my free time too much to the point where clients aren't interested in having me as an emergency line.
I'm sure I'm leaving money on the table, but I'm a one man show, and I have trust issues with relying on others, so here we are.