[ZombieArmy]

to quote an old ad:

" sometimes you feel like a [ prime ], some times you don't "

Peter Paul Almond Joy & Mounds - "Feel Like A Nut" (1980) - YouTube

so find good " experienced " copies and get both

Wish they had dark chocolate almond joy. I want the best of both worlds

[zapp]

Check out older discussions about the 20-40.
20-40 has all zoom advantages, plus weather sealing.
I used 21 & 40 before the zoom was released. 21 broke twice on me with focus trouble. In that case you still have the 40. The zoom never failed. Filter thread on the zoom is awkward, not the same size as most other Pentax lenses.
21&40 felt smaller than the zoom for packing.
After trying both, today I would opt for the two lens option - unless you don’t like changing lenses back and forth.