when i press ctrl while hovering over a backpack i can see items that i need on the far left, however when i open the backpack they are not there. i cannot access these items and need them.

I dont understand the issue can you provide video or screenshots?

Even with an empty inventory those items in the far left green boxes (circled them) can not be removed from the back pack. Including when the back pack is opened.

Same back pack in first image but opened. Those two items are not there.

you are using outdated resourcepack:
the button is here

you can click it and it will work, it just doesnt show because resourcpack is outdated