AA policy is not to through-check bags on separate tickets -- even to another oneworld carrier; so I certainly would not expect them to through-check to Austrian on a separate ticket.

AA will arrive at Terminal 1 (the non-Schengen terminal); Austrian will depart from Terminal 2 (the Schengen terminal). The two terminals are connected, but are some distance apart. (The Airport website says it's an eight-to-ten-minute walk.) PRG does not offer a free connecting bus, but there is frequent, local bus service that connects Terminal 1 to Terminal 2 (Routes 100 and 119). You can buy your bus tickets at a staffed desk in Terminal 1; or at a machine in Baggage Claim at any time if you have Czech coins -- not bills -- or if you have a chip-and-pin credit or debit card. You will need one full-fare 30-minute ticket (24 CZK) for yourself, and one half-fare 90-minute ticket (16 CZK) for your checked bag. (No bus ticket is needed for carry-on baggage.) Bus travel time from T1 to T2 is two or three minutes.

More information about the bus service here: https://www.prg.aero/en/public-transport-buses

As to whether two hours is enough time to make the connection with checked baggage, I will leave to others to weigh in about; I flew into PRG for my first time ever on Saturday, and am flying home tomorrow. But you should check what Austrian's cut-off time is for checking a bag at PRG.

Good luck!