If we're moving from a Gigabyte Z490 Vision D to a Gigabyte Z690 Aero G with DDR4 memory, we can in fact carry over all of these parts:
- DDR4 memory
- Power supply
- Possibly even the CPU cooler, but that depends on the CPU you have now and the new CPU you plan to use; different CPUs generate different amounts of heat (TDP), so the CPU cooler must be rated to handle the new CPU
- Everything else can be reused except of course the (a) Motherboard and (b) CPU
A fresh installation is a good idea, but not strictly necessary. On the Gigabyte Z690 Aero G, we need to use product name
MacPro7,1 so it would be best to generate all new serial numbers. This might cause some iCloud confusion. But we can always try it and see what happens.
I generally recommend a fresh installation with new serial numbers. Then we can either (a) manually copy all our documents, files and applications to the new system or use Migration Assistant.