Card Recs for maximum travel benefit

Coming to the experts for your suggestions.

Spouse and I will be doing likely 3 European trips and one Japan trip in the next 4 years. After that, too far out to say. Looking to get us combinations of cards that can help us maximize travel benefits, through SUB, free hotel stays, transfer partners, etc. Every time I start to research I get overwhelmed and just stop trying. We have some bigger purchases we will likely make when we get new cards to hep get us some of the SUBs etc  

We both currently have Chase Sapphire Preferred cards (different accounts) with about 200k points, and we share a Costco Citi Visa card. Both of us have credit scores over 800, combined income about $160k.

We’re open to fees within reason especially if its a card we may not keep forever,  but we obviously love to get good value and lower cost. 

Loose plan was to each open a card before travel in 2027 and again in 2028, possibly a third in 2029 but I’d say generally I’m not interested in having more than 4 cards at any given time for my own sanity

Thanks, experts!