You have 1 - Amex platinum. Has great travel benefits, like lounges, but if you don't travel, why pay $450/ yr for it?
I think you're a bit heavy on the spg. Good for hotels, not so good for airlines.
Chase points (UR) are flexible for airlines, as are Amex MR.
Right now, ending today, Chase Ink has a 60K signup bonus instead of the usual 50K. The Chase business United Explorer is a good one to apply to as a 2nd in a 2BM. (Chase often pulls separately for biz and personal apps even on same day)
As a whole, someone putting near 50K each month on cc, could really rake it in big by opening new cards regularly.