I found something else, not really sure if this is 100% correct, but in their obtain netherite run, if you pause at 00:11 and go frame by frame, you see the f3 screen kindof "cutting?" the pause menu for 3 frames. This might be due to wp or lagg, or might be a cut to hide f3 or somthing idk, also they have heart regenerating after they load in
The run:

Omg

She told me that she didnt really enjoy speedruns anymore and this was the last thing that made her quit. Very sus but I dont know. Also she apparently practices categories by going in a superflat world for 2-3h and practicing every crafting and chest looting. Also theres an option in windows that removes the 'speeding up' of the cursor when you move it. I dont really know how to explain it but when you turn it off crafting and chest looting is much more consistent. I personally think that the obtain netherite record is legit bc I could see myself getting that time (I played obtain netherite for like a week after I got the 6.615 and got way better). What we both also used was a macro to tp to the best spawn for practice and its really helpful. The all minerals wr tho... It really looks very TAS like and Im not sure but her leaving now made it way more suspicious. I could try to get the crafting in that speed as she did in the all minerals run when my pc is repaired. PogMan