You need to read the fine print on your ticket and your travel insurance to find out what actions are available to you. Most travelers would never put valuables in their checked luggage.
Second, if it were stolen, there's nothing saying it was TSA vs baggage handlers
Third, call all your card issuers represented in your checked wallet, report them stolen, and ask for replacements to be sent
Fourth, carry important things like your wallet on your person/in your carry-on in the future
TSA employees are poorly paid and poorly trained, so easy thefts are common.