I do not have another computer but I do have another case that has another motherboard, psu and ram kit in it which I will try the cpu & both gpus in soon. I tend to be really paranoid when moving pc parts.
The 5600x (my current cpu which was thought to be dead) with the 1050 ti works in a sketchy pc I made out of my previous parts (msi mpg b550 gaming edge wifi, patriot viper steel 4400mhz 2x8, silencer mk3 1200w (literally 8 year old psu) and it all works.
the 1080 Ti however, still no display and the lights on it are red on VGA
As for being paranoid about moving pc parts that is understandable. So much can go wrong. Especially if "wrong" to begin with.
However, doing some careful pre-planning, reading up on specs, configurations, compatibilities, installation, being methodical, changing only one thing at a time, use proper tools, and taking your time can and will avoid many potential problems. Clean, well lit workspace. Keep it neat.
And learning to stop and go back if something is not right or does not seem right is important. Take breaks, clear your mind, regroup as necessary.
Actually that all holds true for just about any sort of work or effort.