How do I fill/set blocks in unloaded chunks

[tall blade]

How do I do this, can I load these chunks in and then fill?

(not using custom entities)

[lavish loom]

one way could be to schedule the fill to happen when the chunk is loaded, but idk if thats what youre looking for

[tall blade]

I want to load the chunks immediately can I do this with tickingarea?

[lavish loom]

idk i think it does, but that's generally not recommended. since they are limited to 10 in each world & things could break if the player or another addon already used up all 10

so you should just use entities to load the chunks