Sorry I should have been more specific… It doesn’t work this way for third party remotes like the Logitech harmony remote + hub. It has the old FFWD action from older Apple TV’s where you can scrub forward at three different speeds.
As the OP said, since tvOS 14.3, Apple changed the behaviour of the default player. A quick press on D-pad right or left during playback now performs a 10 second skip forward or back. A long press on these buttons operates the normal seek mode. It would be great if Infuse could match this default behaviour for consistency and convenience.
There is a suggestion from a couple of years ago which was being looked at. Hopefully it will get implemented now that Apple have shown the way.