User jAm-0 has issues getting into and out of his phone's bootloader. He attributes this to the bootloader being corrupt and wants to replace it.
User return.of.octobot provides instructions to allow reflashing the bootloader. One of the steps is to run fastboot flashing unlock_critical, which allows the bootloader to be overwritten.
Overwriting the bootloader is the only way to hard brick most devices, and fastboot flashing unlock_critical tells Android you don't care and are willing to take the risk. Hard bricking makes a device unfixable on the software level.
jAm-0 has another question and receives responses from return.of.octobot and another user, nrage23. Again, no disclaimers are given and the word "brick" isn't even brought up.
jAm-0 hard bricks their phone.
That's fair, though I've found it hard to find information on these topics. I still only half-understand what I'm doing when installing a custom ROM or sideloading Magisk because I usually just blindly follow the accompanying steps
Poor/cryptic documentation sucks for sure. It means you have to risk your device which just increases the difficulty to start with that kind of hobby for sure. The only alleviation I can think of is to again hit the forums. Ask about the risks involved and how to mitigate them if possible.
I'll admit that I've never made a post on XDA. I just created an account -- hopefully I can get some of my burning questions answered