Fwiw the TP link bulbs usually have a local API that Home Assistant has an integration for. You can use that and block their internet access - unless they’ve removed that feature. I only used one of these briefly because someone gave it to me. Usually just use cheap ZigBee bulbs. I would throw that one out though as someone else said it’s likely been compromised already…

If you’re open to code CAD look at build123d

You can simply use a DNS provider like Cloudflare DNS along with ddclient

Nice