Earlier quoted context omitted.
Machines trick you into thinking you're progressing. The first time I went from Smith machine squats to free weight squats, I couldn't walk the next day (went from 150kg on the machine to 80kg free weight).
I just don’t think my knees could handle squats. I was thinking to do a leg press with lower weight. Like 20 reps.
fwiw high weight + low reps (4-6) if you want to get stronger, lower weight with more reps for getting bigger (8-12)