highly evolved biplane fighter

You could try a more radical approach
Saab_viggen_underside.jpg
 
The problem with high speed biplanes apart from the drawbacks already mentioned is that at 'high' speeds the airflow between the wings behaves very oddly, giving rise to induced drag on an epic scale which pretty much limits what can be done.
 
The Italians did fit a DB601 engine in a CR42 giving it a top speed of 320+mph. Uncharactoristicaly sensibly they didn't put it into production, leaving their limited allocation of German 601 engines for their monoplane fighters.

A 601 engined Avia B.534 for East European Allies of Germany might have been possible, and could have done reasonably well against the Soviets for the first year or two. Even later it could have been used protecting the supply lines from partizans.
 
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