Hey man! Do not worry at all, what you're feeling is absolutely normal (even though it sucks!) It's your mind and body's way of saying 'Hey, let me get this in my own time' - Just know, you're not failing, you're
learning.
The key really is
'time'
Getting to the point in your playing that you're looking for is going to take just that, a whole lot of it - and that's the best part! It's all positive growth and patience
If you consider what you're actually training your hands to do - it can help to think of yourself as a kind of robot (let me explain, I know that sounds odd) Basically it takes loads of tiny, really well calibrated sets of 'motor skills'/muscle memory in your hands to get to the point where more difficult techniques will feel manageable/natural on your instrument. At the moment you're willing your hands to do really intricate things that they maybe need more time to get used to, and the more time you allow them, the quicker you will get there, because you won't be at war with yourself.
I used to sit with my guitar and do exactly what you describe just now - playing exercises to warm up, and then maybe launch into the afterlife solo
- I would get so frustrated and throw my guitar down, my wrist all seized up etc and pick half shredded. I wanted to play fast so bad that it's all I tried to do - and those were wasted months in hindsight. What I didn't think of was taking my time. And I swear to god, the minute I sat down and said to myself 'It doesn't matter if I play fast, I'm just gonna play 'clean, accurate and relaxed, and the speed will come.' - my chops drastically improved. I wasn't putting any pressure on my limbs to perform at a certain standard, I was allowing them time to. I got out of my own way and my playing got where I wanted it.
So in a nut shell, breathe, relax, get excited for the learning process and learn to laugh when you hit these walls, cause it's a never ending cycle. The guitar plays hard to get all the time and it's the thrill of the chase that keeps us all sitting down and working on things! Not to be cheesy but - slow and steady wins the race haha.
You're going to look back at this thread one day and smile, man!
Hopefully this helps!