Cannot search bugs -- so these may be duplicates

Not that I should expect the website to function any better.

Issues:

1) Tempo in playback

I have a section in a tune that needs fermatas. When the fermata is played, the tempo is PERMANTLY changed. Never mind that a fermata is not a tempo change.

My score playback (to hear if I made a mistake) goes from 180 to 6bpm in six measures. No tempo change should have happened at all.

To illustrate the tempo problem, I have attached a very simple score.

2) Copy and paste.
If I copy a section that contains accidentals, the accidentals go away from the original (more than half the time, at least).
When I paste to a new location, what I get appears to be random. Copy/Paste is more trouble than reentering note-by-note for

Female, Tenor, and Bass vocals
3 guitars
Bass guitar
Organ (hammond)
Piano
Drum kit

Copy/Paste is totally useless

3) Note entry into chord when key signature is not "C"

I have been working on a piece written in B-flat minor (5 flats)
As a transition chord I need to play a "C" chord on the guitar.
I enter C, E, G, C, G (guitar) to get my notes.
Actual output is
C, E-flat, G-flat, C, G-flat (as expected)
Using the mouse to select the notes, and the up arrow on the keyboard, I adjust it to
C, E-nat, G-nat (as expected)
I copy this chord, and paste it into the next meaure
Every time I get
C, F-double-flat, G-flat(uhhh, what?)

Selecting the F-double-flat, I use Ctrl-J to chang it to it's enharmonic equivalent
Now, read closely, because it changes it into
E-flat-double-sharp
(WHAT??? I've been playing music for more than 50 years. Never knew that a flat-double sharp existed)

I have used MS since 3.0. I have published several music books in 3.x. I am not a beginner.
I gave Musescore 4 a fair shake. I have been trying to use it daily since it first came out.

Honestly. Do the world a favor.
Everybody that worked on this POS needs to throw away their computers and never try to write another line of code again.