If you're already running OpenWRT then I personally recommend Wireguard over tailscale if you have the time. It's not hard to set up at all and takes the third party out of the loop. OpenWRT has excellent support for Wireguard configuration and export of configs to the devices you want to connect (install client, import config). The only "gotcha" is needing DynamicDNS (assuming you don't have a static public IP)

Tailscale is definitely super-simple but this IS the self-hosted community ;D I always prefer removing third parties at every opportunity.

Please note that the Tailscale binaries for OpenWRT are pretty large (even if you cross-compile them with compact and strip). Your router might not have enough storage for it.

If that's the case, you might work around it by only storing the tailscaled binary on persistent storage, because that's the daemon which runs the actual connectivity. The tailscale binary is only used for making configuration changes, you can copy that to RAM disk, use it to set config params, then delete it.