Far more injuries occur in the gym with your “vanity lifts” than occur at home where people focus on their individual needs, body and form.
But yeah, there’s no way to do 3 rep sets with 90% of your 1RM without a spotter.
This old man is totally over that. You will be too one day as recovery from injuries takes up increasing amounts of your training routine.
I doubt it. I’ve been lifting a long time. I am very careful not to ego lift. I also change my routines regularly. If I am bulking I may go with 3 to 5 rep sets at 70-90% of 1RM but I will be off this routine within 90 days and moving to a routine with higher reps and lower weight. My favorite is circuit training with 8 rep sets at about 60-65% of max. It is a monster cardio as well as weight resistance workout.
I used a bench press program that went off of reps with % of max for years. It works. 5 sets on flat bench and would get stronger the next week. Heavy sets was 3 reps at 90% of max, 5 reps at 85% and 8 reps at 80% of max. Those 3 sets required a spotter if you wished to live. NFL used the system back in the day for strength training. It worked very well.
Every time you got your 3 reps at 90% on your own you added 5 pounds on the bar the next week. Everytime you went up 10 pounds on your 90% the other sets went up 5 pounds.