They're remarkably heat sensitive, especially cheap ones. Some bulbs would gladly run for 10 years in a room slightly above freezing temperature, but put them in a semi-enclosed fixture in a normal living space, and they're dead in a few months. Fully enclosed fixtures destroy them in no time, unless you buy really exotic bulbs with truly massive aluminum heatsinks, rated for high temp operating environments. I can't even find domestic suppliers for those, and had to order from China.

The LEDs are surface mount (although big surface mount components, so not particularly difficult to work with). I desolder them with hot air (although you can totally do it with a soldering iron), then use them later as any other surface mount LED. I don't have access to YouTube right now, so can't search for you, but there are tons of videos covering how to desolder and solder surface mount components. I'd be willing to bet there are multiple videos covering this for LEDs specifically, too.

Actually it's a terrible idea - those LEDs have been overdriven to hell and back, their luminosity and overall lifetime decreased.

LEDs are super cheap. I bought few hundred pre-covid for $3.