android 9 how to unallocate space for apps that no longer exist?

[Lucky5]

I have a Razer phone 2 running android 9 (latest update I can get)

Ive had an sd card in my phone for awhile but never used it until recently i was running low on space, so about 2~ weeks ago I went to the section to migrate data to the SD card, I found it odd that it doesnt let you see/pick what goes into the sd card but whatever, after it had finished I noticed the storage on my internal storage did not go down at all, then i checked to see that most of my audio files and videos were just copied onto one drive and not deleted off of the other making trying to move it completely pointless, some apps got moved but not the ones I wanted to be moved. the main issue arose when I tried to delete apps I no longer used, they got deleted, I dont see the icon nor can i find them anywhere on my settings but they still take up space, I also wanted to go and delete the audio files and videos on my internal storage since they were just copied (from what I can tell, its kinda annoying to navigate the files) but when I plug in my phone to my pc and allow file transer, I can only see the 128gb SD card, not the 64gb internal storage like I used to be able to do before I migrated data to the sd card, so deleting the copied files is tedious to do. The discord screenshot is referring to the SD card claiming that apps are taking 15gb instead its only 500mb

going to storage settings and selecting "free up space" will only prompt me to remove saved images

also if I go to photos & videos and go to my images, it says its taking up 5 gb, and theres nothing there

[Lucky5]

After doing some more google searches I genuinely cannot find any solution to my storage being filled up by essentially nothing