Unknown printing issue with a Bambu P1S (Help)

Hi everyone :D

I'm Romain, i'm from Belgium and I am new to the world of 3D printing !

English isn't my native language, so sorry for some upcomming mistakes :-P
(I print with some Bambulab PLA filament with a Bambu P1S, with a 0.4mm nozzle).

I started printing parts 2 weeks ago and I'm faced with my first real problem that I can't solve alone... and I'm coming here to ask for your help because - by making failure after failure - I'm gonna quickly run out of filament.

I modeled plates made up of 8 cartridges inclined at 25°. When printing a single cartridge, it prints well, whether with layer heights of 0.2, 0.12 or 0.08mm : (IMAGE 1 IN ATTACHED FILES).

There are still small "bubbles" in the center of each cartridge (less on the 0.2mm) which I cannot explain. Do you know what it is ? But now, when I try to print the entire plate, with all the cartridges, this is what it gives... Here is an example printed at 0.2mm and the other at 0.12mm : (IMAGE 2 IN ATTACHED FILES).

On the 0.12mm version, there are the famous bubbles, and in addition the upper part of the cartridge is very poorly printed. On the 0.2mm version, there is no longer the bubble problem but the upper part of the cartridge is still poorly printed.
Here is a close-up of the problem when printing at 0.2mm : (IMAGE 3 IN ATTACHED FILES).

So I'm a little lost... This poorly printed upper part is printed without support, but at a low angle of 25° and without the software asking me for supports (which I prefer to avoid because other elements have to slide inside the cartridges).

And what surprises me is that the same isolated cartridge (see first photo in green) prints much better, with almost no bubbles in the center and with the upper part of the cartridge very smooth.

Do you have any information to guide me towards a solution? Somes clues ?

Many thanks and everyone have a nice evening,

Romain