Are you doing your sets hard enough? I had online clients do a similar approach and ask them to film one of their sets and they were NOT going to what I can failure… true failure is not being capable to move the weight even 1 centimeter more…and you have to try! When I do a style of training like “Best Damn” on my last rep, when I hit failure I try to continue pushing with all I have, trying to move a weight that can’t move for at least 3 seconds.
Furthermore the pump is not an indication of growth, at least not with this system.
Can you add one exercise? You can do whatever you want… it’s your training. Would I recommend it? No.