I'm fine with it personally, learning about background characters and it's like a short break for him. He does draw 20 pages and does Twitter illustrations. And with how mentally and physically taxing creative works can be. Honestly, rather this than him having a 2-month to 10-year hiatus. Or getting sick from working too hard, then worrying about their health. ╥﹏╥
I mean he has a history of creating dark and serious stories (Tista and Gekka Bijin). However, his Editor suggested doing something lighthearted (banning him from doing anything dark), because he was having creative difficulties (which is probably the reason for the short missions and the 2 weeks). It's a balance, Endo still incorporates elements of his style into the comedic story. Which is one of the reasons why it's a success. Spy x Family, in some form, is his "rehabilitation" to find his way back to drawing manga.
Here is the interview: https://fandomwire.com/i-remember-banning-him-from-drawing-anything-dark-spy-x-family-saved-tatsuya-endos-mental-health-from-declining/

I love and hate the “extra stories”. I love them because they're enjoyable, and I like getting to know the characters a little better. But I hate waiting so long and not seeing any progress in the main story.