So here's a bit of background as to where I'm coming from, since I have no idea how else to start this.
The first phone I used for myself, with no one else having control over it, was the LG G7 ThinQ. In that phone, I could control individual app volume just from the volume overlay itself, without having to open a specific app for it. At least, mine did, but apparently that's not normal after a quick search. Now, after a while, the phone started warning me that it was encountering more and more bugs, so I thought I should probably get a new phone before that one gave up on me. So, I did, and got the S23U - which is a piece of trash, and why I ended up switching it after not even two years. The only good things about that phone were the Stylus, since I live in Canada, and the sound assistant app - which gave back the individual app volume control, whilst also giving me the new ability to play media from multiple different sources, at the same time - so YouTube, and YouTube Music for me.
Now, on Graphene OS (Or well Pixel OS in general) I can't do either of those things, and the only thing I've seen that might work, ShizuTools, requires Shizuku, which I haven't been able to get to work because I'm either dumb, or the tutorials online just suck and jump over steps.
So here's my question, how the hell to I enable what I would consider basic functionality on this phone? Preferably, without rooting the phone because while I bought the Pixel9P yesterday specifically to installe Graphene OS on it, I would rather not have to wipe everything on it again.