'I' class is a deeply discounted booking class and ineligible for complimentary advanced seat selection even without paying, you would be able to get a seat allocated at check in time. There is no entitlement to seat selection in advance

If so concerned on being able to select seats, then allow for the additional cost that may occur when comparing fares so as to compare against total cost - many people are not obsessed on what seat that they will get and wouldn't pay extra for it

If you want to know full details on fare type being purchased, perhaps book directly with QR

Looking at r/t ORD-DOH as an example in September
Business Lite is $5222
Business Comfort is $7703
Business Elite is $8832

I would suggest that your $5300 fare would likely be a lite fare and so ineligible for complimentary lounge access

When booking directly with QR, it does detail whether there is a fee for seat selection and whether lounge access is included.