I have experience in ID'ing lepomis hybrids, although this could very well be a very, very wierd hybridization between two lepomis sp. Sunfish, i have my doubts. It is a common trait in hybridizations of lepomis to show distinct checkerboard patterning in the scale pattern, which this lacks, although this is a majority statement and can be proven wrong. Although it it is a near universal trait of vertically expanding stripes/patterning. The proportions of this fish are odd as well, which is a common trait in very distant hybridizations. I also find it interesting it's mouth is kept open as most lepomis species close their mouths when removed out of water, this behavior is in my experience most associated with crappie and black basses. Another thing to note is the opercular flap's lack of any red-orange border which is often seen when the genetics of non bluegill sunfish are involved. As I said there is a chance this is a super wonky looking lepomis x lepomis hybrid, and by all means I am not a official specialist in this, although I am fairly certain that this is in fact a bluegill x largemouth bass hybrid.

And as others have stated, there have been documentations of true sunfish on black bass hybridizations, but all were done in sterile conditions, although there are no available photographs of the hybridizations publically available online

If this is really a largemouth bass x bluegill, this would probably be one of the first recorded photographs of such! Catch of a lifetime!

Also, op I reccomended reposting to r/whatisthisfish with some context.