tablet – Bootloader / BIOS, intermittent ROM and correlated risks. Why are Android devices easier to build than PCs?

I have a solid experience in the installation of different operating systems (Linux, Windows, …) on PC. I would like to try installing Linux on an unbranded and low-cost Android tablet purchased in 2015. I spent some time browsing the web and, from what I understood, there is a risk that during the flash procedure the device may be damaged. So I read a lot about how to back up the ROM using TWRP and all related issues. I would like to have some explanations on the subject below:

Scenario 1:
I have a PC, if I want to try another operating system, I can only format the hard drive and install it, in any way there is a risk of damaging the BIOS motherboard. The motherboard and the hard disk are separated, so no problems can arise.

Scenario # 2:
I have a tablet, I want to remove Android and install an improved version of Android or a Linux distro suitable for mobile devices.

  • Why is there a risk in this scenario of obtaining an unusable device?
  • Is it because in this case the motherboard and the memory of the unit are grouped? So cleaning the memory will also erase the configuration settings of the motherboard?
  • Do we have here the equivalent of the BIOS configuration?

Thanks to everyone who wants to explain.