Need help in running test cases in parallel

Hello fellow developers,

I have automation testing project which uses playwright, specflow, .net . I want to run test cases in parallel.

Treid following configuratuion which runs the features in parallel.

<ParallelScope>Fixtures</ParallelScope> 
<LevelOfParallelism>8</LevelOfParallelism> 

but i need more control over test cases execution as my automation test count has surpassed 250. What other options do i have?