Listen, Jaki, you're getting mostly good advice here. The thing is . . . you really only seem interested in lounge access, and the deal with these credit cards is that they only really have value if you can take advantage of most of the package of benefits they offer. I think most of us here would say that your current batch of credit cards is very low-value relative to what's available out there. You can see from the comments that there are a lot of good benefits with the Platinum, but you have to be willing to spend the time and energy to take advantage of them. It's not clear to me that you are. If you were flying Delta, I'd say you probably would get a lot of value from the lounge use with the Platinum. But you're not--you're flying UA and Southwest. The first thing that came to my mind was the Chase Sapphire Reserve, which would give you full Priority Pass access, including restaurants (really good for using at SFO), AND would include both UA and Southwest as transfer partners for the points you earn. But I'm not sure you're even interested in earning the points, are you?

If you ARE interested in getting more serious about earning with your cards, I'd go ahead and get rid of the ones you don't use. The Apple Card is OK as a daily driver, since you get some cash back. Same with the Amazon card, particularly if you use Amazon a whole lot. You might consider getting rid of the rest, and adding a travel card, either the Amex Plat or the Chase Sapphire Reserve. Never use a card that isn't giving you something back. It's amazing to me how many people don't know this (you clearly do, given the cards you have).

So that's my 2 cents.