lr-puae 2021 run game too fast (Bomber Bob)

[roditore]

Hello,
I've installed latest retropie version on a Pi4 8gb.
I've a problem with game Bomber Bob for Amiga.
I use lr-puae 2021 (but I've tried also with lr-puae) and the game, with default settings, run very fast, and it's impossible to avoid shots by enemies.
I've changed some settingsi in retroarch, that is:
Cpu Speed: -80%
Cpu Cycle: Exact Cycle time

and now shots from enemies has almost the same speed than the origianl game (I use the longplay on youtube to compare).
But, the main problem is suddenly in a level game came back to run fast for a while (1 second or less) and so new shots increase their speed and are unpredictable.

Ths is obviously annoying and frustrating (So I am not playing it anymore).

Is there a way to emulate it better?
I've also tried amyberry, but it doesn't work. Too many problems.

[testudo]

Are you playing it under NTSC or PAL settings? If the former, maybe try under PAL.