The Lee Progressive will not try drop powder if there is no case in the stage and I believe the newer ones also will not feed a primer either so it is entirely possible to operate it by feeding only one case at a time and thus allowing you to focus completely on each stage until you feel you have it mastered.

WRT the Lee Progressive press itself, it is certainly excellent value for money but IME they all need a bit of tinkering to get them working well. You certainly have the tinkering skills (not everyone does) so it's just a matter of carefully attending to each area one at a time. This might be dangerously unconventional but take some time to CAREFULLY RTFM to understand it all and do not skip over bits which might seem unimportant or unclear. As it the norm with 'merkin manuals, it is not written very well and easy to miss something important.

If you are going for multiple different cartridges then get extra die plates so you can avoid the tedious die set up process each time you want to change cartridges, just swap the entire die plate, and if necessary the shell holder, and crack on.

I think that there is now a four stage version so that the bullet seating and crimping stages are separate - this is a godsend - I found that with the combined seat/crimp die as used on the three stage version there is a tendency for it to shave bits of lead off the bullet as the crimp compresses while the bullet is still seating.

I would also avoid the standard powder dispenser plates - they obviously only have discrete sizes and it seemed to me that the ideal loads were always somewhere in between, particularly if you want light target loads. I believe it is possible to mount a Lee Perfect measure instead and again with a bit of fettling it works very well.