Difference is that reaching the semi's in the CL is somewhat of a bummer for Bayern whereas it's a monumental achievement at Ajax. If Ajax go out at the groupstages this year, people will say it's a shame, but not a disaster to go into the EL from third place behind Valencia and Chelsea, for Bayern it would probably be a sackable offense.
Either way, I don't think a trainer's influence is that big anyway, so I'm sure he could do it. Of course he's done well at Ajax, but he's also had the good fortune to have world class talents like De Jong and De Ligt and a few very high profile players for Eredivisie standards like Ziyech, Blind, Tadic and Tagliafico, which is a result of Ajax getting rid of their salary ceiling of 1 million per year. I'd say removing that is at least as big a factor for their success as Ten Hag is. In that same light, I doubt Kovac would've done as poorly, had he still be able to play a 30 year old Ribery and Robben instead of the kids they got to replace him.
I think the coaches that can make a team more than the sum of its parts can be counted on one, maybe two hands.