Hello, it is useless to do this:
execute as @a[scores={progress=3}] at @s run execute as @e[tag=pblock,scores={run1=2..}] at @s run setblock ~ ~ ~ podzol
(the at @s is useless because you don't use the position of the player and run execute is just too much, it lengthens the commands for nothing)

That's better:
execute as @a[scores={progress=3}] as @e[tag=pblock,scores={run1=2..}] at @s run setblock ~ ~ ~ podzol

On my side, I tried in a flat empty world, impossible to make it work.

You really need to rethink your code, putting everything in one loop is really not good, because you execute 400 lines every tick when you could execute 10 maximum.

Simple example, you have 59 lines that test if the player has a "progress" score that is equal to 5 and if so, something happens.

Instead of doing 59 tests, do one test:
execute as @a[scores={progress=5}] run function one_pack:progress5
and in this function you can put all the commands that run if the score progress is equal to 5.
This will be 58 times more optimized.

Little advice, you can use the worldgen, to create empty worlds, it would be cool if the datapack would automatically create an empty world when you launch it in a new world.
(a flat world without anything)

Good continuation to you, your datapack has potential but there is still a lot of work, good luck ;)