Sounds to me like a completely productive workout. You don't have a specific fitness goal right now so everything was great for a general fitness focus with hypertrophy rep range work. You found a machine you like and did some stuff you have been dreading to do which is a bigger deal than you are allowing it to be. The hardest stuff is the stuff that makes you uncomfortable, you chose that path, that is not unproductive it is one of the more productive things you could do after the way your session started. I say great pivot and stop beating yourself up.
By the way feel free to tell me to hush, but if you are getting frustrated right now with training, it might be a good time to just go into the gym to have some fun for a while. You don't have a specific goal right now, and you seem upset or at a minimum unimpressed by your performance on a lot of sessions. I think you might enjoy yourself a little more if for a while you just went in and did the lifts you love, chase the pump and not sweat the performance so much for a little while. Just enjoy Bro'ing out on the weights like you did back in the day when you were enjoying just being in the gym. Bottom line if you get somewhere between 3-0RIR you will grow and having variety and fun working out is why you do this thing anyway isn't it? The goal setting and plans of action aren't what made you love lifting, loving lifting made you want to do those things. So maybe let your hair down a little, do some instinctive and fun training until you set a serious goal you are going to need a serious plan for. I just know for me having a goal or multiple goals that I want but am not committed enough at the moment to follow takes the joy out of training, because I know I am not doing what really needs to be done to chase any of them. I have to recognize those times and do what makes me enjoy the gym the most just to keep moving in the right direction. Then I start having fun working out again.
Anyway, my point is I would love to see that you are enjoying yourself in the gym again when I read your posts. Rather than you feeling like you are fighting an uphill battle which is the impression I get lately.