You did't mention budget. The Epson refurbished 5040ub is the best bang for you buck. From lowest to highest the Epson 3200/3800, 4010 and 5050ub are 1080p 2x eshift projectors with 1/2 4K resolution. Describing your room, viewing environment and content would help a lot with a better suggestion. One of the many XPR DLP's might even be a better option with 1080p 4x shift for full 4K. True 4K is out of the $3K range of this forum.
"Smart enough to know better, to old to care" ------ Dedicated Bat Cave Home Theater, JVC RS49U/Mitsubishi HC7900DW Projector, 110" 16:9 Jamestown screen with variable power masking for CIW 2.50:1 to 16:9, Marantz 7009 with 7.1.4 Atmos with Ohm mains,3 DIY Subs (2 15" (1 ported, 1 sealed and a 12" 4th order bandpass), 1 DIY butt kicker, Custom Built HTPC, 18TB DroboFS NAS