Hi, SORRY I'm not a musician but just a few thoughts. Firstly, it really isn't because you have a stupid ****ing brain, we KNOW that that's not a problem as you CAN do it.
It's maybe as much as your belief in yourself, your worries, your concerns, stress, anxiety holding you back and perhaps if you're a little less hard on yourself.....?
Is there any particular time/s in the day when you're feeling a little more relaxed or any particular places which you could use for music/recording that may help?
Would it help not to plan the recording and just do it spontaneously in a session where you're just practicing/playing for enjoyment (whenever you feel like it) then maybe a little less pressure/stress?
But if you're recording could you do some retakes and throw in a little editing afterwards to make it as you want it?
Are you really sure you want to be doing things like Air on a G String though, from what I know that's a really hard piece, and for a perfectionist with anxiety............What are you doing to yourself?!
I know, I know..........you like...........but surely there are other genres of music you appreciate too??? And some that allow for ad lib if you feel things going off track a little. Naturally you can still love pieces like Air on a G String, but sometimes musicians can like listening to some genres but like playing other genres can't they???
I mean, obviously try throwing in all the strategies for managing anxiety, but if it comes down to it isn't the most important thing, that you can actually enjoy/feel connectedness, fulfillment, meaning within playing. I mean music can be so powerful, you don't want to lose that for yourself at the cost of stress/anxiety in performing "perfectly" do you?
So if that's a different type of music then so be it. And there will be plenty of people who will really appreciate other genres too.
But just a thought, to help you feel/know you are more "in control" musically have you ever tutored/helped someone to learn to play?? Then you're also going to be seeing upfront, while you're automatically telling someone what to do, just what you DO know, your REAL skills, which although they ARE there you may be doubting at times right now?? Maybe find the right student???
Best wishes
Alison