What, specifically, is giving you trouble? System menu? PS1 games? PS2 games?
You mention bob deinterlacing, which tells me you’re likely working with PS2 games running in 480i. If that’s the case, you’re looking at 1440i with line3x, which is a very atypical video mode, and it doesn’t surprise me that your display doesn’t like it. You’ll need a scaler that supports that mode in between your OSSC and display if you want to use that.
If you still don’t want to use bob deinterlacing, consider using passthrough for 480i and letting your TV do deinterlacing and scaling.