Often you can get by just starting a PowerPoint presentation, alt tab away, and let it run in the background. It'll keep the computer from locking and you don't need to install anything that might look suspicious.
CGP Grey did a video on this subject a little over a decade ago.
But here's my number
I'm currently looking at setting up Reolink cameras on a homeassistant setup.
Not sure if it perfectly meets your requirements, but it should be ad free and closed system.
I used 1/2" thick puzzle mat, which was plenty to keep things floating. I used a 3" hole saw, but only cause I had it already (ran it backwards so the teeth wouldn't grab and tear the mat.)
A yoga mat would probably do ok, but I had to add a little bit of weight to the corners to stop the mat from flipping up in the wind (see previous post) so the yoga mat might not be able to support that extra weight.
If you didn't need the cookie cutters anymore, you could probably put a board on top of one and smack it with a hammer to cut circles in the yoga mat, but it also may not work. You'd have to experiment a bit.
Tromeo and Juliet (1996)
https://en.m.wikipedia.org/wiki/Soyuz_MS-10
Falcon 9 never had an abort with crew onboard, while Soyuz has.
Not sure why SpaceX is in this group, except "cause musk", since they're objectively the best rocket company out there.
The rest are obvious, but the Falcon 9 is the cheapest, and most reliable rocket.
Call the fire department, they have detectors that they can use to look for gas leaks and other things that can set off a detector.
You can also call your gas provider. One of those two should be able to track it down, it could be a lot of things, but two different smoke detectors going off in the same location is a huge red flag.
Best case, you have something kicking up fine dust, worst case, you have a smouldering electric fire in your wall somewhere.
Don't panic, but also do not ignore this.