There shouldn't be any newer boards coming out. Intel is certainly done with Z590. AMD might release something to refresh X570, but probably not. They might also release slightly updated CPUs (See 3000 series XT chips), but again, they have no real need to. Next on the list is AMD APUs, so the replacement for the 3000G, 3200G and 3400G.
We should be seeing Zen 3 based Threadripper and Epyc from AMD soon, that will eat up a lot of the Ryzen chiplets and it would make more sense for them to push forward with Zen 4 on a 5nm process for 2022. Right now Apple is consuming the 5nm node for their M1 chip, but it is possible we will see Ryzen 6000 mobile processors late this year.