Excelblem I think is fine in his short video/compliation format, but I can't fathom watching someone do all the slow burn exploits he does cap levels like when he spammed Framme's chain guard in chapter 4 to get her to 20 actually be done live on stream. He does have runs where he doesn't just kill his own units for money. His FE11 and 12 runs were not KMUs but legitimate scuffed ironmans, and I believe he ironmanned all of Fates too. He also did Sacred Stones with 0 strength which was one hell of a trip to say the least.
He also did 3H as a Byleth solo by the last half of the game and did all the KMU stuff by the time skip, which despite him spamming his way to level 99 with minimal exp gains he managed to beat that run in 40 or so hours because he didn't do any tutoring or shit because he killed his units. Which is extremely funny and sad how his run is about standard for a 3H run despite him spam grinding, but because he didn't tutor he beat the game as fast as anyone else.
Mangs to my knowledge did like Engage for the most part, I have no idea with Mekkah, I couldn't get a good read on his perception the few times I watched him play it he just seemed lost as usual with new Fire Emblem just like he was in Conquest. Neither really played maddening really either, well Mangs did a maddening ironman and lost everyone except Louis in chapter 5.