The difference is that Frieren is literally over a 1000 years old and her main hobby is collecting magic spells regardless of what they do. We expect her to have lots of variety because we've been shown that. She has a spell to turn grapes sour, and the first thing she does with it is visit her dwarf friend who likes sour grapes. Her favorite spell is still the one that grows a field of flowers that she learned from Flamme, and now they retcon in a meeting with Himmel where she used it and charmed him to look for her when he started his journey.

Methode can't be older than her 40s.

Richter's main job is making, selling, and repairing magic tools in the city where the Mage Association branch is. They did establish that it is his day job, similar to how Denken's is being the Empire's Court Mage.

If we get background info on Methode and why she has such a big variety of abilities, I'd change my mind.

Edit:
The series specializes in retcons to make bullshit make sense later.