Does AF/KLM serve Belarus? Or do you/they then fly on a separate ticket or a codeshare on another airline from CDG/AMS?
Star Alliance airlines LH, OS, LO & TK all fly to Belarus but only LH has a 1 stop option from DTW all the others would require a double connection in ORD/NYC and then the European hub but that increases chances of getting an award ticket. United being in that alliance and being a transfer partner of Chase UR makes it an attractive option with limited cost for annual fee membership. I'm not involved with the Citi TY program as I dropped from it 5 years ago. Amex can be great particularly if you get a targeted offer for a high promo signup which would almost make it to two award tickets via AF/KLM or using Aeroplan for Star Alliance partners.