I bought a 2016 IS 200t F Sport in 2021 and traded it in for a 2018 GS 350 F Sport AWD last September. The IS is noticeably smaller than the GS. I'm in the car 95% of the time alone. The IS was comfortable for a weekend trip with my wife. The main complaint with the IS was it had the 2.0 Liter turbo motor. The lag was pronounced, but once the turbo spooled up, it was great merging and passing.
I tried to find a pre owned IS 350 F Sport AWD near me before I bought the GS but not many for sale. I like the refreshed IS design. The IS 350 would be the way to go IMHO.