I don't want to have to change all my computer again two year after the upgrade.
This depends what you need, non of this systems could play AV1 media at higher resolutions.
AV1 is the successor of of HEVC and gets heavily pushed by those small companies like Google, Netflix, Amazon, Microsoft ... you name it and it is highly likely that they rather quick switch to AV1 because there are zero licence fees. First content should be available in ~1-2 years.
So if you buy today you have already have an counter at your hardware
So better buy rather cheap what fits your needs today !
Current price to performance kings are these various S905 boxes, for Intel there is only J3455 or J4205 because only these HW has HDMI 2.0.
For the best CPU from Intel (performance/price wise) the G4560 are no HDMI 2.0 supporting mainboards available that are not extreme expensive (cheapest is 160€ - more then an complete NUC/Brix/ZBox).