I'm also into re-using old tech right now.

I'm also planning to convert my 2015 iMac to a screen soon. I have all the parts and just got my 2019 Ender 3 Pro 3D printer up and running to print brackets for the install based on the files from the video in your post (now handily referenced).

I can also reuse 32Gb of its 48Gb of DDR3 SODIM RAM in a 2012 Macbook Retina that I just refurbished and converted to Ubuntu for my kids. I have Linuxed 2 of 3 more than decade old Macbooks and they work really well.

The other RAM & storage will we re-used in a $55 Zimblade NAS.

I'll have to do a post on it.