My SSD is full of games like Apex and Fortnite, wanted to ask if I can download Fortnite and Apex on my HDD
Yes of course
Why not
Of course you can. When installing the games, you simply select the other hard drive.
If you don't want to uninstall it, but want to move it, you can read this here;
https://gegamenews.com/index.php/2019/02/18/so-verschieben-sie-fortnite-in-einen-anderen-ordner-ein-anderes-laufwerk-oder-einen-anderen-pc.html
https://answers.ea.com/t5/Technische-Fragen/Origin-Spiele-verschieben-statt-neu-herunterzuladen/td-p/2522986
