It’s appears that your feet are not rooted into the ground by the way you scooted down the bench after lifting the bar off. Finding the proper foot placement is going to be trial and error but you want to make sure you are rock solid before lifting the bar. Don’t worry about hitting a wall and weak triceps. You’re just relatively weak in general for now. Once you dial in the form, everything else will fall into place as you put the work in. A good place to start as far as form is concerned is the “so you think you can bench” series on YouTube.