I realise now, I just watched them both and Galaxy is better in just about every way except maybe physical strength, but yeah I agree with you
Rungvisai is no slouch, as George said, and I don't think he immediately gets overwhelmed or destroyed, since he is a very strong and crafty ring general, and has some very good notches on his belt. However, Srisaket is also inconsistent at the highest level, and has shown to use perplexing 'gameplans' despite his ability (Estrada 2 - what the hell was he thinking!). This may work against him. Galaxy was an immense fighter, with immense power and a gifted intuitive sense despite seeming like a blockhead and being naturally straightforward. I'd predict an early war that Galaxy gets the better of by mid rounds, before a devastating KO.
Duh, he may be the shortest of the Valhalla-Weight boxers but not the least lethal by a long shot a battle between Khaosai Galaxy and Rungvisai is akin to comparing the Elephant taking note of every Ant it crushes on his journey to feed, a pointless affection that would draw too much mental effort to grasp, so much like the ant Rung will be unnoticed by the infinitely superior Khaosai in the process of complete Annihilation.