This is a foolish requirement.
The casino team are trying to just stress you, why can't they ask for your wallet address and put that in blockain scans and look into your past histories themselves? Some online casino requirements are crazy at times, if this is bank account requires it is different, but asking for your income statement that is publicly available on the blcokchain sound stupid.
Anyways, you don't have a choice than to give them what they want, use blockchair or any other and download the PDF, I am not sure that Electrum wallet has that feature.
To me it does not sound like the casino staff is actually asking about some data available on the Blockchain, like an address an collection of linked addresses which transacted with one another in the past, it rather seems the casino is looking for proof OP actually earned the money in a legitimate way and the money he has deposited onto his gambling account does not come from illicit sources, like traffick of narcotics or theft of digital assets.
Otherwise, I would not understand why a casino would ask for something they could easily check themselves with the addresses used by OP to deposit in the past.
Assuming my assumption is correct, it would imply to go for full KYC protocols and also give some legal work statements to the casino, so they can see whether the money previously deposited by OP matches with his alledged salary. It is the first time in a while I see a casino asking for some much personal information, probably withholding some of the money won by OP, as no casino asks for those documents during the process of creating an account.