Horrible fuel mileage, it doesn’t matter what I run 87 or E85 it’s 10.3-10.6?

I drive the SUV listed above that I have been working out of for the last 2 years. When I first bought the truck 10 years ago my average MPG city highway mix was always around 15-16 on reg 87 and 12.5-13 on E85. Now for some reason it doesn’t matter what I run 87 or E85 it’s 10.3-10.6. Should I not get better mileage all together and should it not be better on 87? When I first started using it for work, I was at least averaging 13-14. In the last 2 months I’ve replaced all 4 O2’s (checked them and fuel trims with a scanner and they seem to be working), 4 new stock size tires, plugs, wires, heads due to a crack in the #5 cylinder causing low compression, all new upper gaskets, water pump, fan clutch, thermostat, temp sensor, full front suspension, brakes, rotors, hub assemblies, regular oil changes, new air filter, and I’m sure there is more. I know most of that doesn’t matter but just covering every single base. Any help would be appreciated, I can’t afford another car right now, and I also can’t afford to be filling up every day or two. Thanks again.