Hi is AMD Zen + or even AMD Zen 2 Motherboard compatible with an Zen 3 CPU?
It's very confusing, this may help:
Zen 1, or simply Zen at first = Ryzen 1st gen = 1000 series CPU's
Zen 1.5 aka Zen+ = Ryzen 2nd gen = 2000 series CPU's
Zen 2 = Ryzen 3rd gen = 3000 series CPU's
Zen 3 = Ryzen 4th gen = 5000 series CPU's
These are the only Ryzen CPU's that work on AM4 motherboards but you HAVE to be sure of the BIOS revision that the board has. If you get a later generation and put it on board without BIOS support it won't boot until updated. SOME AM4 motherboards have a BIOS flashback feature that let you update BIOS without a CPU.
I agree that if you're looking at a Zen 3 CPU..or even Zen 2...the best choice is to get a 500 series (chipset) motherboard. But even then you have to be sure of BIOS revision as there can be some new-old stock motherboards still unsold.