Help me with my first printer ender 5, i'm ready to give up

Attachment 15525
On my prusa I have only ender 3 as an option. I downloaded last version from an official site.
Attachment 15526

I should have Noted that I am using Prusaslicer 2.3.0 alpha 4

I got that build of prusa slicer and tested it. I printed XYZ cube with cura and prusa slicer, on cura flow was 150%, on prusa i ajusted it to 150% manualy,here are the results:
1). Top and bottom are better on prusa slicer, but main problem i have with all prints stays same: there are gaps between walls and i can just put my nail between.
2) Infill is much better on prusa, on cura it just goes wrong
3) Walls seems good, but they seem more solid on cura
Pics(Left is Cura)
Attachment 15529Attachment 15530Attachment 15531Attachment 15532
Also I reprinted default cat with pre-made g-code, there was no such problem here(exept flow was at 150%)^
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There are links to both cubes and cat gcodes.
Can u pls say why there are gaps between walls on all sliced models and why there is no such problem on cat?

https://wdfiles.ru/jv1x
https://wdfiles.ru/jv1y
https://wdfiles.ru/jv1z

After printing the Calibration cubes, I do not know where these G-Code came from though they printed in excellent condition.

If you sliced them with Pruseslicer post your 3MF file will look at your settings.

Cubes were sliced with cura nd prusa slicers, i didnt get 3mf that time, but i recreated that project:

https://wdfiles.ru/fj3K

I see all my files have underextrusion which i can fic and wall gap problems.

or you can just set it up as #other# and just tell it the size of your print volume - that's all i did for the sapphire pro.