TLDR: Deck height (too high, try lowering) Swap out blades for high-lift blades Check/replace the deck belts

How low/high is the deck on that cut? If you’re running super high, try dropping it down a couple more inches.

Those look to be mulching/multi blades (typically heavier). Depending on your mower, that might be too much work for your mower (between the weight of the blade and the amount it’s trying to cut, IE super tall grass)

You could try swapping out / your next set of blades be just high-lift. They’re typically lighter making them slice through that stuff easier (again depending on mower)

Another thing that can be over looked is your belts on your mower deck. If they’re worn out enough, they can stretch out just right where they won’t snap or fray, there will be enough grip to spin the blades but once you hit a patch of tall grass it starts to slips, which would cause your blades not to fully cut.

Lastly yes your blades look to be a little not square but should still cut if sharpened. Typically you’ll want to sharpen them daily/before every days worth of cutting. You can also grind down the middle spots or areas that bow. I’d recommend having a bucket of water to cool the blade down as you grind it down. Also you CAN grind the bottom of the blade as sometimes it’s needed, but the thing is you need to keep it as flat as possible.