[DonVoigt]

You need to fit the side plate to the frame and to clear the take down lever.
Changing the frame won't cure that problem.

The side plate has to fit the curve of the frame, the tang of the side plate has to be the correct thickness to clear the take down lever, and the semi-circular cut in the front of the side plate tang is cammed rearward to the frame by the take down lever, and must also be fit to get the takedown lever to close firmly but with thumb pressure.

You can expect to pay $250 to $350 for a frame, if you can find one that suits you.
I may have a Mauser frame that would suit.
Post pictures of the condition of your frame/pistol.