I haven’t had the same experience with DuckDNS. It was great for a few years, but for about the past year it would randomly go down (preventing access) or my domain would get flagged as spam. I ended up buying my own domain from cloudflare but I’m planning on investigating Tailscale at some point.

Yeah, I have a Nest Mini that randomly died and is now just sitting in a box. This might be the perfect project, assuming whatever’s broken would get swapped out.