Can you get a silicone/flexible bowl and use it instead? It might come out easier

If you use baking paper screw it up, then unscrew, screw up again a few more times. This allows the paper to be much easier to work with and will stay in place better. Or alternatively use a round cake tin and cut it to shape.

Spray the bowl with non stick cooking spray. Or freeze the bowl before mixing it

baking paper or heavily grease the tin. Make the mixture a little moister or take it out 5 mins earlier so it doesn’t dry out as much but is still firm

Line the bowl with grease proof paper, this will prevent it sticking and you will have a perfectly turned out cake every time.