Help pls (Replacing main SSD)

Hey. So I want to replace my 250GB SSD with a 2TB SSD because untill now i used my 1,5tb hdd for gaming.

Right now my pc Has: 250gp SSD, 1,5TB HDD

I want: 2TB SSD, 1,5TB HDD

Ive been told that my motherboard doesnt have space for another SSD so I am planing to replace the SSD I have.

The Problem is that my windows is on the 250GB SSD and I am not sure what the best process for replacing is.

Do i have to move the OS onto the HDD and then move it back to the new SSD once it is replaced in my PC? Does it even work like that? Can I just copy everything from the 250BG SSD into a folder on the HDD, Replace the SSD and then drag and drop it back?

Im kinda lost.

Preferably I want the same OS i have right now (Win 10) because fuck Win 11 but i am ambivalent to installing something new as long as it isnt WIN11 (Please no linux I dont wanna learn that rn).

The reason I am still on Win10 is that I am waiting for steam OS and am not too attatched to the files on my PC anyways.