Normally females have a lower jaw that is has a blue tint.
But maybe because the lights (are they tinted a certain color?) , maybe the blue substrate, but everything looks a oddly green, kind of washing true colors out.
I edited your pic a bit to try and get a better idea, but it didn't really help.
The larger appears to be male, but unless you can see more blue than the pic shows, I can't tell about the smaller one
The only reason I’m really even asking any of this is because I’ve had my littler one almost a year and she hasn’t connected with anyone. I just bought the big one named (bowser) btw a few days ago and as soon as I put him in the tank they attached automatically and inseparable ever since. Found this a bit odd
Big one is def a male.. I'd lean towards female for the other based on looks and what you're describing their Interactions like... but the pictures are a bit blurred and washed out so hard to tell for sure