wheres filtered seed glitchless? or the site used to get seeds? pls help

in the 1.12 oneshot seed, the chest that gives pickaxe in videos only gives gold and bread for me pls help

i want to try speedrun perfect seed but the world download link says "content does not exist"

how to make a minecraft bedrock tas???

I see ppl in ssg runs and they can seemingly speed craft a specific amout of an item in a click, without dragging it off the crafting grid. (Example: https://m.youtube.com/watch?v=ciyYvsDS1kI&pp=ygUHTWNiZSB3cg%3D%3D (Start at 0:20)) is there a hotkey or smthn for this? Shift clicking just crafts all of one item instead of 1 or 2, so idk how they do it

I would like to know if theres a client or smthn that works as a resetting mod. I see the rsg runs, and they reset incredibly fast, it sounds like they clicked 10 buttons in half a second. Also the create world menu looks different. If there is somthing i could use pls tell me?