That would be much more thematic.
Cybertron Trilogy Megatron vs Frieza:
• Both are galactic conquerers, with similar colour schemes (Later on, in Transformers: Cybertron, Megatron turned into Galvatron, he had the exact same colours as Frieza), who lead armies to subjugate and take over the universe for their own gain.
• Both speak in affluent and fancy ways, blinding their sadistic cruelty and desire to see everyone suffer before them.
• Both are more willing to slaughter innocents and their own men on a whim.
• Both are so selfish that they would freely kill their entire army if it means getting more for themselves (with Megatron/Galvatron was going to kill his entire army until they rebelled against him and Frieza killing all the Saiyans when they were working for him).
• Both are more than willing to throw down by those empowered by the power of gods to achieve their goal.
• Both came back from death three times (Frieza after Namek, returning in Resurrection F and returning for the Tournament of Power and Megatron after Armada, his unexplained return after Energon and willing himself back to life after his collapsed in on itself in Cybertron)
• Both of their willpower is so high that after suffering humiliating defeats at the hands of Trunks and Metroplex, the two would through sheer force of will achieve shiny metallic super forms that significantly increase their power without any precedence said beforehand that such a thing was possible for them.
• And both have attacks with “Death” in the name, with the two both even having a move called the Death Cannon.
Japanese G1 Megatron: Silver alien tyrants with golden forms.
Clearly, the Megatron with the golden form is a much more thematic MU for Frieza.