@droftarts thank you for the reply and sorry for the late reply.

After sending the message I continued tinkering and searching for clues of why that happened, and I've discovered what was the problem:

By using the BLV mgn profile on Cura, the special option "Set Relative Extrusion" is disabled, meaning that when I was applying the "set relative extrusion" command inside the gcode, the acual extrusion values inside the print gcode were still absolute and exponentially told the machine to extrude more and more filament, more than it could do.

By removing the relative extrusion command, the printer worked like a charm.
After that, I've tried using other slicers like Orca, and it managed to convert to relative extrusion with no problem, with also a lot more of options for me to customize. So I'll probably stick to it from now on.

That was genuinely my bad to not have thought of that before, tomorrow I'll set this post to resolved for the posterity.

@jdandcoke P defines the tool number in M563 eg:

M563 P0 S"hemera" D0 H1 F0

T[number} selects the tool eg:

T0

Ian

@gerrard
It looks better, let's hope the print doesn't shrink too much this time 😉

I saw a simple way to improve your printer: the tall idler bearings should be supported from both ends.
idlers.jpg

@dc42 thanks for your answer.
Are layer comments the same for every slicer?
Could you answer two more questions, please:

How DWC determines layer change? If I'll place any G-command (one or block of commands) with summary Z, DWC will take it, divide per layer height, then show me correct info? You wrote, that it looks for Z moves , so, it looks like "last Z" minus "pre-last Z" = "layer height" for DWC, then "last Z" / "layer height" = "layer quantity"?

Thanks once again @Phaedrux.
I honestly thought it was not being applied as it went 0.25 then to 0.20.
Is there a way to show the actual height as opposed to the corrected height, ie 0.25? For me it confirms that I have my settings in Cura correct.

(Damn, I had a 5 minute video, powerpoint presentation and the likes to show how it was not working!! 😉 )