So, if I understand things correctly, your KYC3 did passed and verified. When the support staff said that "it's being investigated" [or the similar words to it], they're referring to the account itself, not the KYC process.
In short, they suspected something wrong with your activity, so they investigated it. Normally, casinos will ask for certain level of KYC prior to this investigation to tie an account to a person. [Unless I understand wrongly] that KYC itself is successfully verified, all you need to do is wait while they confirm and check your latest sportsbetting activity.
Rest assured that if you did nothing wrong and/or did not utilize forbidden technic, they'll release your fund when they're finished with it.
Would you like to show my activity in sports?) There's a ridiculous amount of money
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The very big money in sports I bet?
Kindly understand that, at times and probably more frequent than what we thought will be, the value of bets does not necessarily dictate an account to be checked or not, in sense that because someone do small bets, they're very less likely to be scrutinized while big bettor will get investigated.
Yes, a check following a big win is almost guaranteed, but this does not directly means small betting will not be checked. If a casino [or their provider] think that the player might cheated or use forbidden technic, they will investigate, regardless of the amount.
I'll assure you again that if you did nothing wrong and all of your bets are placed, won and loss, in fair manner, they'll conclude their investigation with similar conclusion and will release the fund.