My Dyslexia

I am 35 a student ( honestly ) but always struggled with ADHD and holding long term relationships, does anyone else have any problems with this? The social anxiety is difficult to cope with too.

Its beyond my experience, but I suggest you understand how this manifests itself and then how another person might see it.
Once you understand this , then you can start learning strategies to minimise the impact. Speaking or learning from other people with adhd would seem a good way to go.

https://www.google.com/search?client=firefox-b-d&q=dating+woth+adhd

Social anxiety is an issue on its own, but I would also be understanding how that affects me, the strategies I can use to make a difference and then slowly introducing change. Maybe a counsellor via your GP would help with that.
As much as you might be scared you need to push your boundaries in small ways to build up momentum and gain some self-confidence that you can effect change in your life plus the consequences of failure/ knock back are far less than those of doing nothing.
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Anxiety
https://www.nopanic.org.uk/no-panic-youth-hub/
https://www.anxietyuk.org.uk/get-help/
https://www.counselling.cam.ac.uk/se...f/anxiety/view
https://www.nhsinform.scot/illnesses-and-conditions/mental-health/mental-health-self-help-guides/social-anxiety-self-help-guide
https://www.nhs.uk/conditions/social-anxiety/

Self esteem
https://www.mind.org.uk/information-support/types-of-mental-health-problems/self-esteem/about-self-esteem/
https://www.nhs.uk/conditions/stress-anxiety-depression/raising-low-self-esteem/
https://www.talkspace.com/blog/category/self-esteem/

I would really love a long term relationship and to be more social, i'd like to know how to do that with more confidence.

I dont know how it manifests itself but I tend to research and understand, then work on a plan of things I can do to improve my chances.
How you feel about yourself is also a boon.
Its then a case of looking in the right places and the same challenges anyone faces plus the smaller chance that you meet an adult capable of accepting you for who you are in all aspects. Some will and some will not. You cant control that but you can put yourself in the best position possible.