Unsure what to do with my computing degree

Take your time. Look through your options and select which one is best for you. Take a gap year if needs be to decide what you want to do and to rest after the hard year you've through.

Hi I have completed my computing degree got a 2:2 yet I am not sure whether I’ll be able to find a career within computing this has left me a little anxious and worried and I don’t know what to do next.

Note: I don't work in tech, so you might want a second opinion from someone who is.

I have friends who graduated with degree(s) in computing/CS, and quite a few of them went self employed. It's not to say that you can't work for a large organisation, but you often come across job descriptions where they make a long list of things that they want and you end up doing something trivial and niched after you get the job (usually examples of HR handling the whole recruitment process with no input from the IT department). Getting employed in a large tech company is usually very challenging anyway.
Having said that, there is usually a number of big named employers who look for graduates to go into tech roles with a 2:2 degree. These usually won't be within the tech sector though e.g. banking, education, healthcare, etc. You would need to look further afield.
You can go for medium and small companies, but these companies often require you to have more experience and be more independent i.e. if you don't know what you're doing, expect a short tenure. You would also be expected to wear multiple hats, because usually there is not enough specialised IT work to go around and you can end up doing a lot of other things as well.
On the other hand, startups is tend to be a hot area for tech people, but you would be expected to learn and work fast. It's a dynamic area where there is a lot of development and a lot going on. It's also an area where there is a shortage of people with strong IT skills.

One of the things that can boost your application is having relevant professional certificates on your CV. Whilst it's maybe something you don't want to hear after studying for X years, the professional certificates can often be more relevant and applicable for the jobs you want in tech than your degree.
I don't know which area of tech you intend to go into, so it's difficult to point out which certificate you would need. I wouldn't however, do any random certificate just to fill in gaps or go randomly applying for any jobs. For example, if I have a CompTIA Network+, there's little chance it would be in anyway relevant for any role in cybersecurity. I would also make sure the certificates are professionally recognised in the country and specific area you intend to go into, as these can vary across different areas (your degree should be recognised in any country though).
The typical areas people look into are: cybersecurity, programming/software engineering, web development, and networking. There are other areas, but you will need to be specific.

The other thing that I would strongly recommend is to build up a portfolio of work to show off the recruiters and employers. I would include stuff you have created (apps, websites, add-ons, software, etc.) on a website, whose link you should include on your CV.
One of the big things about employers is that they want to make sure you have done something similar to what they want you to do i.e. have experience in what they want you to do. If your sample work is not as technical as what the employer are looking for, it's not going to cut it. The closer your work resembles to what they are looking for, the more likely you would be invited for an interview.

I think the most difficult thing that you would need to handle is the competency tests that they will throw at you during the interview. They expect you to be proficient, accurate, and fast, so you would need to be really on point to even get through. You can be competing against people who can solve programming or technical problems within seconds, so you need to achieve something similar to stand a chance. You should be able to google for such problems to practice from.
They also say the difference between someone who isn't very good and someone who is (i.e. not getting hired vs getting hired), is that the person who is has came across the same problem a lot more times than the person who hasn't, and has solve the same, if not similar, problem significantly more times than the person who hasn't. If this holds any truth, then you always have a way in.

Ideally I want to do a role in junior tech support or first line technical support or even second…

You should be fine then. Support tech roles from what I have heard require next to nothing to do, and they tend to be plentiful.
Having said that, you might be borderline overqualified with your degree, so I would be wary about including your degree in your CV. If you had any other work to fill in the gaps in your CV, so much the better.

I know of some graduates who went into IT support before they ventured off to do something else in tech (usually with a significantly higher salary).

I don't think a professional certificate would exactly be of benefit for support roles, but if you find yourself struggling to get the role, then I would recommend looking at the following: https://www.comptia.org/blog/best-it-support-certifications

Again, you might want a second opinion from someone who works in IT support first.

How would you advise me going forwards to how to apply for a IT Support Tech role. Do I need to modify my CV or is there a specific platform to look out for is the requirements to the job hard or…