I’ve tried tailscale and cloudflare tunnels in the past and ended up just using PiVPN to set up a WireGuard VPN on my Pi5. Tailscale for some reason was very slow for me, and cloudflare tunnels have a 100mb limit iirc which isn’t ideal for streaming. PiVPN is quite straightforward, it sets everything up for you and all you have to do is forward a UDP port. That was the bit I was most worried about, but, unless I’ve misunderstood something, because a UDP port will just ignore invalid requests to the outside world it will appear closed so it’s not very risky. It then generates a key for each device which you can scan from a QR code onto your VPN client. I have my phone set to auto-connect to the tunnel when I disconnect from my home wifi network and the tunnel is fast enough that I’ve accidentally turned off my phone’s wifi connection before and streamed a TV show through the tunnel over mobile data and not noticed any difference in speed.
I love mine. It’s pretty unobtrusive but there’s a ton of open-source applications available on the store. Probably the most similar to the original Pebble (besides the new pebbles of course) right down to the MIP display. Tried a pinetime but it’s very limited by comparison and an IPS screen on a smartwatch is a terrible idea.