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Btw is the msi b550 gaming plus overkill for r5 3600?
Yes, it probably is a bit "overkill" in the sense that it has a pretty strong VRM, way stronger than needed for that processor. If also not interested in future upgrade potential - that VRM is quite capable even for an R9 5950X - then this would still be overkill. But there's more to a motherboard than just the VRM.
The board features some pretty slick styling but if not interested in building a show-case system this might be overkill for that. If you're not worried about PCIe gen 4 for the GPU and system NVME drive then most B550 (or X570) is overkill too.
There are other considerations for selecting a motherboard that have little to nothing to do with the processor on it. Things like motherboard audio chipset, LAN chipsets and capabilities, WiFi (or lack of it), SATA and USB port complement.
Alternatives depend on what's available to you in your area. B450 and some other B550 boards might be cheaper still but you give up any upgrade potential for PCIe gen 4 devices if that's important. But beware especially the cheaply built B550 boards that don't support PCIe gen 4 since giving that up probably makes it a better deal to go with B450 chipset if not interested in gen 4.
If available Asrock B550 Phantom Gaming 4/ac might be cheaper for you.