alternity and golden megatron clear dbs as a whole (alternity can probably clear the expanded canon stuff but that’s more debatable)
UT depends on how you scale the ending arc because it’s really complicated and weird, could go from Megatron being stomped to being even or a stomp in his favor depending.
Super/Ultra Megatron could be a competitive match, I would lean towards them though
any other version unless I’m forgetting something major should lose. The next highest is like g1 with planet level stuff and IDW has a planet level suicide attack
Maybe Cloud Megatron could do something but I haven’t finished those stories yet and I didn’t see any actual universal or above DC feats, just a lot of multiversal travel and claims that with Sara’s power Megatron could reshape the multiverse
Forged to Fight might have some juice but there aren’t transcripts of all of it so I have no clue, just seen a few videos and read what text is available. Good lore for TF cosmology as a whole but not as much scaling for anybody in particular within it