Camera Manual Mode limitations

[CaptainBadKid]

 I own a Samsung Galaxy f42 5g. Recently, through my college, I have been half forced, half willingly delved into photography, and part of that has been exploring the manual settings of my camera. While exploring, I have found that a lot of the basic features normally afforded in manual mode are not available. I cannot adjust the shutter speed or focus manually. So I downloaded Open Camera. There I found that I still could not change shutter speed, and that I could only access the 16mp camera, and not the 64mp one. Then I found another app. This one could do shutter speed only down to 0.5 sec and still limited to the 16mp camera. At this point, I cannot afford any paid alternative (professional camera/new phone) but would like to have full control and access to the features of my own phone as I feel that would be enough. Is there any tool, app or setting that I can use to gain this kind of access and customisability. I am willing to go as "jank" as needed, and rooting the phone is also on the table. I just want control over a product that I already own.