@aadil-gl
So, SortOrder is in the InductionContent list that is NOT the document library and is numeric.
Your Document library has a Lookup column in it that references the InductionContent list?
No, you should not have an invalid comparison in your formula nor should you have delegation warnings in your formula. The first will cause you problems, so I'd suggest we get the formula right.
For simplicity, I'd recommend only a numeric column in the Doc library to hold the ID of the other list item, or if your data goes the other way, then a numeric column in the list that will hold the ID of the doc library item. A lookup is fine, but there are some extra steps needed to reference it in PowerApps.
So is your intention to get a list of doc library items based on filtering the list by some guidestep variable?
I'm not completely clear on your requirements and design.