I have friends with over 200K miles on their 4 cylinder cars. They run fine and neither puts out 175 hp. I raced a 122 hp 4 cylinder car for 5 seasons that would hit 118 mph top speed but give 40 mpg on the highway. I know a number of these cars that have exceeded 300K miles. I’ve had 3 turbo-charged 4 cylinders cars that all produced over 175 hp, 2 of which went 200K combined, all 3 of which would cruise all day at 75 mph. No worries about 4 cylinder cars.
I’d stay away from CVT’s in general but especially from Nissan. If your only choice is a CVT, make sure you change the fluid every 30K miles, religiously!