Bulldoggswimmer

Hello, I am new to the forum and would like to ask for help. I purchased a home with an infinity edge pool a long time ago. It never worked correctly and has always been a royal pain. The pool is approximately 25K gal, just a guess. The overflow basin is large, not sure of the gallons. My plumbing is : one return line from the catch basin ( weir ) and one return from a bottom drain on the main pool. There is a selector valve to choose the percent of draw from each section. The pump is 1.5 hp old pump with a large Hayward sand filter. There is one main return line with 4 different return pipes into the pool. The flow appears to be fine. I also installed a salt water chlorine generator on the return. The problem is, this design is terrible, whoever built this pool. I can not have the pool drain working effectively if I want the water to flow in the catch basin . And if I want to have the pool drain working, then the catch basin stays stagnant still and becomes disgusting because its not part of the circulation. When I have %50 catch basin, %50 main drain as my return, the pool operates very marginally with poor cleaning of both areas. So.... I want to rip it all out and fix it correctly. Can you please give me advice on how to properly plumb this pool so I don't have to fix it more than one time. I appreciate the help....