First-time user misery: fixing up imported PDF

I used the MuseScore online PDF importer, which gave me a score that had a number of issues. In trying to fix these issues I ran into some very frustrating usability barriers in MuseScore.

OS: macOS 12.6, Arch.: x86_64, MuseScore version (64-bit): 4.0.0-223472200, revision: 5485621

The mscz file produced by the PDF importer is attached below.

The main issues that I ran into are all centered around the same problem:

1. The PDF importer misjudges the duration of a note
2. This results in overfull measures in the mscz file
3. MuseScore makes it difficult to adjust note durations

Example issue #1:

In measure #4, two tied 8ths in the piano RH were imported as two tied quarters. Now the RH piano measure is overfull (5/4 instead of 4/4), and the LH piano measure had an invisible rest added in beat 3.

To repair this, what I want is to be able to tell MS simply that a note's duration was wrong. Select the two misread quarters, change them to 8ths, and I would expect the RH measure to contract down to 4/4, and the stray rest to be removed from the LH to also contract it down to 4/4.

Instead, what I have to do is: select the misread quarters, convert them to 8ths (which creates two unneeded 8th rests in RH), then cut one of the 8ths and paste it in its correct location (which leaves me with an extra quarter rest in the 3rd beat of the RH), then delete the 3rd beat from the RH (which also deletes it from the LH)

Example issue #2:

In measure #21, 16th quintuplets were imported as plain 16ths in piano RH. Now the RH piano measure is overfull (by 16th), and the LH piano measure is padded by one 16th rest. (This same measure also has the 8ths misread as quarters problem in beat 2.)

What I expected I could do: select the 5 16ths, click a button to convert them to quintuplets, the end.

To repair this… I can't. I just can't. I tried a lot of different things, but in the end there is no sane way to convert non-tuplets into tuplets. I ended up just inserting an extra beat before the broken quintuplets, manually writing in the quintuplets as they should be, and then deleting the broken ones. Oh, and this also caused the RH and the LH to be misaligned, so before I could delete the broken quintuplets, I had to move the quarter note in the LH from below the broken quintuplets to below the the real quintuplets.

In short: the most common error that I have so far encountered with the PDF importer is that it gets note duration wrong. The most painful thing to repair in MS4 is a note whose duration is wrong that is surrounded by other notes whose durations are not wrong. I think that in order to make the PDF import experience better, you need to improve not just the importer, but also to make the editor better at making the kinds of edits that are going to be part of the import fixup flow — which are naturally different from the kinds of edits that the editor is currently optimized for, which happen when you're writing music from scratch.