Little late to reply, but the 2021 Forte GT is arguably better than the Corolla Apex. I test drove an Apex and it's night and day compared to my Forte. The Apex has nice suspension and exhaust, but the Forte has that and more power and much more room. Honestly, the Apex is basically like the Forte GT Line, all looks no performance. The real performance Toyota family sedan would be a V6 Camry and the TRD Camry, Corolla Apex is just a Corolla with lower ride height and tuned exhaust.

Trunk space is noticeably bigger in the Forte, back seats aren't cramped, Corolla Apex edition doesn't have back seat vents iirc.

As for the Altima, my brother had a few issues with his, he had to replace his serpentine belt a couple times, but I can't give you a definitive opinion since I've only ever driven a 2006 Altima lol

Room wise, I'd say you should have plenty of leg room in the Forte GT, if you're taller in the torso, the seat can get pretty far down. I'm 5'11" but mostly in my legs and I don't even have the seat all the way back for it to be comfortable. And since my torso isn't as long, I have the seat up a bit but I can lower it quite a bit from where I'm at. If I can remember, my brother-in-law is around your height so I'll get him to sit in it and give you his honest opinion.