I think you are just going back to circle here. RTP display is for the total win amount of all players divided by the total wager on that specific game meaning it’s not same to everyone. RTP varies on each user experienced for example you sucks on playing then your RTP will be low.

Theoretical house edge is what you are pertaining and I doubt this will be helpful on proving your case due to the small sample size. No one here will have free time to check your bets 1 by 1 to determine how do you play so I suggest seek help of 3rd party arbitrator to deal with your case.