Nozzle height adjusting for every print
It sounds like your bed is unstable. This is what I had to do with my Tronxy X1, and I fixed it by installing a decent bed stabiliser. Now that I have a stable bed, I only have to re-level it occasionally. However, the Tronxy X1 is a cantilever printer with a single rail for the bed, not an Ender 3.
I would suggest that you tighten the bed-levelling springs as far as they will go whilst still leaving sufficient movement for bed levelling, and re-position the end-stop switch. Then re-level the bed. If that doesn't work, try fitting stiffer springs. Upgrades are available for the Ender 3. If that still doesn't work, look for bed stabilisation solutions for your printer.
Note also that the bed-levelling knobs have a reputation for coming loose on the Ender 3. Tightening the springs (or fitting stiffer springs) may cure this, but some users fit locking nuts to stop the knobs moving.