At this point both Intel and AMD DDR4 sockets are end of life, so the same is true of both at the moment.
Getting a B550 board now, you can just get a 5600X and call it day until your next upgrade. 16 core 5950X is possible, but were you doing that I would suggest an X570 board. 5900X is probably safer on the higher end B550 boards.
With Intel, a B560 board will let you run i5-10400F on the cheap side, or an 11600K or KF on the expensive side. (With Intel you do have the integrated graphics option more cheaply than a 5600G, or 5700G, though not as good, and the G chips are limited to 8x PCIe lanes to any graphics card)
Intel max would be an i9-10850k/10900k with 10 cores, but that high clock speed for games. 11700k is about as fast, but only 8 cores. 11900k is really not worth the price tag.
LGA1700 from Intel should be available end of this year with DDR5. AMD likely early-mid next year with Ryzen 6000 (unless they make an intermediate chip using their L4 cache stacking idea, but those may be XT CPUs like they did for the 3000 series)
LGA1718 for AM5.