Manufacturer says 8-bit Marlin 1.1 works on 32-bit - can it? Or they don't want to provide actual source code?

I wanted to see what settings my printer uses, so I asked support for Marlin source code for my model. My printer uses STM32 and reports using Marlin 2.0, but what they sent me seems to be 1.1 from 2015 and the video instructions they sent me shows that it is compiling for AVR and not ARM.

Most of the code is Marlin 1.1 form 2015, but there is a lot of config files from 2020 and the folder and file structure is completely different than Marlin 1.1. Here is what I got.

I have exchanged about 10 emails, and the support insists this is the correct firmware. Could I be wrong?

My printer is a very cheap Easythreed X1 and I’m blown away how detailed the prints are, with almost no stringing with PET-G, but it prints crazy slow, takes more than 2x more that Prusa Slicer estimates. I think it has an extremely low acceleration set in Marlin conf. And the support is extremely responsive, they respond in less than an hour, but I think they are lying to me.

only marlin above 2.0 runs on 32 bit boards unless they have self implemented the support for 32 bit boards.

but this board isnt a 32 bit board if you should use ATMEGA 1284P …

I have opened it and looked and the chip inside is STM32. I also checked and the same chip can also be seen on the earliest reviews.
I have no idea how could it work, and why are they providing me with older software than what was installed in the factory months ago.