How can I select which drive I want to play a game from if it's on both my internal xbox...

Good idea! After your comment, I did suggest it on the xbox ideas site. Thanks!

Yeah, I usually run the game (PubG) from my SSD drive because it loads so much faster and the game graphics render in much quicker. However, every couple months PubG stops running from the SSD drive for some reason. I get an error (seems to be an in-game
error) that says PubG took too long to start, then it closes and goes back to the dashboard. So when this happens, if I want to play, I either have to redownload PubG again through the xbox, or transfer the game from the SSD drive back to my internal drive
(both of which works fine, but I usually just transfer since the SSD drive works fine and since it takes less than half the time compared to downloading. To get it back on the SSD drive again, I delete it the game from there, then transfer it back to my SSD.
The SSD drive seems to work fine, the xbox always reads it, and like I said, I can transfer the game from my SSD back to my internal with no issues and play it from there. Seems like such a weird issue, I know, but it's annoying when it happens. I have no
other errors or problems with the SSD except for this so I don't think I'm having an issue with it. I just wish I had the option to leave the game on both drives and select which one I want to run it from when I start it, or just start it from whatever drive
I want it to run from, but it always defaults back to the internal if it's on there.

Can I ask why you have the same game on both drives? And why it matters which drive you are using to run the game? That's the part I don't understand...

Yeah, I usually run the game (PubG) from my SSD drive because it loads so much faster and the game graphics render in much quicker. However, every couple months PubG stops running from the SSD drive for some reason. I get an error (seems to be an in-game
error) that says PubG took too long to start, then it closes and goes back to the dashboard. So when this happens, if I want to play, I either have to redownload PubG again through the xbox, or transfer the game from the SSD drive back to my internal drive
(both of which works fine, but I usually just transfer since the SSD drive works fine and since it takes less than half the time compared to downloading. To get it back on the SSD drive again, I delete it the game from there, then transfer it back to my SSD.
The SSD drive seems to work fine, the xbox always reads it, and like I said, I can transfer the game from my SSD back to my internal with no issues and play it from there. Seems like such a weird issue, I know, but it's annoying when it happens. I have no
other errors or problems with the SSD except for this so I don't think I'm having an issue with it. I just wish I had the option to leave the game on both drives and select which one I want to run it from when I start it, or just start it from whatever drive
I want it to run from, but it always defaults back to the internal if it's on there.

Low tech solution, but when you want to run it from SSD delete the internal, then when you want to swap back just copy it over.

In terms of the PUBG issue though that doesn't sound particularly related and I'd generally recommend only having a game in one location of the two.