Sapphire Plus MAXTEMP setting change

[3DNightmare]

Hi,
First of all, HAPPW NEW YEAR folks, and a very heartfelt "thanks very much" to Khunpoum for compiling a WORKING firmware for the TwoTrees Sapphire Plus.
I received my printer a couple months ago, and so far it has been nothing but nightmare.
Original firmware would only allow me to print the cube test file included on the provided SD card.

Now, thanks to you it works.
Since I placed the BMG clone extruder on top in a direct drive fashion for future all metal hotend (Mosquito clone) in order to print with nylon, I also need to change the MAXTEMP setting on the extruder.

SoI have installed VSCode to alter this setting, and although it seems to have compiled correctly and saved the new 300°C MAXTEMP setting on the SD card, the flashing does not take place when turning the printer on with the SD card loaded.

I noticed there is a ZIP folder named "binary-files-for-copy-to-sd-card-2.0.7.2-r4.zip" and this sparks several questions in my mind:
Is it the folder that actually triggers the flashing?
Does it contain, as is, a set of files that prevent my change to be taken into account?
Is it specific to the posted "Marlin-2-for-Sapphire-Plus-V2-gen2" set of files?
Should have the flashing occured with my newly compiled 300°C firmware?
Should VSCode have generated a similar file when compiling? If so, where do I find it (the search function in VScode returns no result)? How do I create it?
Am I missing something ? What have I done wrong?

Many questions, I have always been reluctant to alter anything software/firwmare wise since it is very daunting to me.
Please excuse my lack of knowledge, but I am really lost to this point. Your kind help would be greatly appreciated.

Can someone please guide me step-by-step in order to have this MAXTEMP setting correctly changed, or post a ready to install firmware with this alteration already done?

Thanks so much in advance.
Cheers,