Yea tbh Mettaton while fairly skilled in his own right, doesn’t really scale to Asgore or even Undyne in skill for that matter. He’s fairly capable of giving Frisk somewhat of a challenge in his own special shenanigans he pulls, but doesn’t have the skill, experience, and training of even being comparable to Asgore + Undyne.
With that being said, Spamton should take this FRA. Mettaton only uses EX form for entertainment in the form of a TV show and never really took the Frisk fight completely seriously and was mostly motivated from wanting high ratings (aside from the genocide route but the one time Mettaton was determined and willing to take down Frisk, he blew it because of NEO lol). Spamton on the other hand has been in his base form for all his life, is implied to be fairly skilled in combat, has an AP advantage, likely has the LS advantage, and will most likely go for the kill when blood lusted as he’s a mentally insane danmaku user who only used his first fight with Kris to make a deal and is implicated to be a lot more ruthless when actually fighting. Also, in Spamton sweepstakes he’s implied to have a history with Jevil playing games with him. Likely implying that they have possibly fought or dueled before considering Jevil saw his fight in Deltarune as a game.
In a nutshell, Spamton wins via AP, skill, likely experience, likely LS, being more likely to kill when blood lusted, and FRA
