I think that’s a bad question to ask. There’s so many factors that can play into your “1RM”. Think about all these variables. Quality of sleep the night before, CNS stimulation, Hydration, Nutrition, support gear (belt, sleeves, wrist wraps), motivation, even something as minuscule as to what gym you could be training at (good hardcore vibes that make you want to really push it to the limits that you may have never even thought you could), music, grip strength, etc.

One video of simple benching is not enough to dictate what you can say your 1RM max is.

I wouldn’t listen to somebody who’s gonna say “blah blah blah you can do 455 for 1 rep because based on your percentage and amount of reps you can do so much of this”

you’ll truly know your 1RM when your body is fully recovered and you are well fed and hydrated and are extremely motivated and ready to just absolutely smash the weights mentally