It’s pretty common for newer 3D printers to have WiFi. Start/stop jobs, monitor cameras, or just to have a more capable UI than the built-in screen. Lots of people add this capability to older printers (or new ones with sucky interfaces) with OctoPrint.

Big +1 for Valetudo. I use it on a refurbished Roborock S7+ I got on eBay and it’s fantastic.

Huh, that is funky. Fingers crossed mine survives. I think I’ll go and set up some backups, now that I think about it.

Easy way to avoid this: choose a different port. I think it’s a safe bet the crawlers are just checking 25565. I’ve had a server up for months with zero issues.