If you do decide to build - find a seller who also sells OS and any other software you might want - and is willing to sell the software + hardware and apply the OEM discount to the software.
You, as the builder, ARE the OEM and (at least used to be) entitled to the get the software at OEM price.
In the early-mid 90’s I used a store which sold OEM software to anybody who bought ANY hardware - even a floppy cable.
Then the software houses got all pissy for some reason and they restricted it to people buying motherboards. Yes, they had one incredibly cheap board…
So I went and built a new PC. With help from Senior Beef. It went really great.
I have a SSD that has windows and photoshop and lightroom on it. everything else is on an older hard drive.
I was pleased at how easy it was to do. I had done several things inside a PC before like add a hard drive, upgrade ram and changed a video card so it wasn’t much more to put in the cpu and mount the motherboard to a case.
The only thing I did wrong is that my reset button is my power button and my power button is my reset button.