Nintendo released it on Nintendo Switch Online's Game Boy (color).

Will it be ok to submit results from it?

I think yes but moderators do not notice that yet.

When you submit the score from Nintendo Switch Online version, it'll be accepted.

I don't trust people to not use rewind lol

I submitted my record (from nintendo switch online) a few days ago and it was not approved.

One moderator told me that emulation records from nintendo switch online are not allowed, but I'd love to hear what other moderators think.

https://www.speedrun.com/tetris_dx/runs/znglnplm

As FlynMaker mentioned, the rewind feature is a problem. However a full video would negate that I think. The only other objection I can think of would be if the emulator isn't sufficiently accurate.