The two spring leagues, the XFL and the USFL, have carved out a special rule for their 2023 seasons.
It states that if a ball carrier fumbles the ball into the end zone and it goes out of bounds, or if the ball is fumbled into the pylon, there is no change of possession and the ball reverts back to the spot of the fumble.
This would be consistent with the rule of forward fumbles out of bounds in the field of play. A defensive recovery in the end zone would still be a turnover to the defense.
Now if they can only change the catch rule to one foot inbounds like HS and college we can have faster games with fewer video reviews.