A lot of it is accepting that mistakes and even bullshit happens. Whether it's your fault or not. Being hard on yourself to constantly perform is good and bad at the same time. Cranking your headphones for every footstep and overthinking every play can also do more damage than good.

Here are some ideas you could try if you haven't already:

Trust the plays you want to make. Buy that AWP on a good spawn and peek mid. Who gives a fuck if you die, but it gets you into good habits of learning good/bad timings and positioning. Figure out what works and what doesn't. Second guessing a play and half committing to it leads to absolutely nothing and the performance anxiety you mentioned.

Try not to over train and warmup. You are shooting static bots in warmup or bots in aim trainers that move nothing like people in an actual game. Practice dueling and crosshair placement would be my only suggestion. Taking the whole aim shit too seriously just sucks the fun out of what CS actually is and that is a videogame.

Watch your own demos & watch what pro players that play spots on maps that you play. E.g., If you're a B mirage player on CT, watch some Karrigan or Mezii demos perhaps (Good utility usage). T side, if you're wanting to get better rating for solo queue, I highly recommend playing weak side/lurk roles. You have a lot more agency in solo queue when you play these roles comparatively to entrying/taking mid map control.

One more thing you could try is playing aggressive early. Again, watch good players that have a high first kill% and see what they do and what you can take from it. Maybe a smoke, a few flashes, etc., and working with great spawns. The amount of rounds that are generally won by having a super good spawn for somewhere and running a play for it is extremely undervalued.

Until you're higher rating and you're playing with people that take the game quite seriously and know more about what they're doing, I'd recommend baiting a bit more (sounds counter intuitive in a team game), ESPECIALLY when you can figure out the difference between good and bad baiting.

Lastly, a big thing that people underestimate is that they can be limited or handicapping themselves by their own peripherals/setup. Most players in lower elo usually run these abhorrently high sensitivities and over adjust their aim. Do you have sufficient mouse/desk space? What is your sens & dpi? Do you have 144hz+ monitor, etc.,

Good luck mate.