HDMI 2.1 isn't even remotely required unless you're a gamer... at this stage. As you list no gaming consoles or PC's with the latest model graphics cards, then you'll be fine.
Even then, only certain games may benefit from 4K/120 AND it's not even universally decided whether players will actually like the increase to 120. I know it has zero effect on my gaming (3-5 hours a day)
This industry is not getting cheaper and cheaper, we're simply convincing ourselves that we have to push the cheapest option to customers. #makesonosgreatagain
