sorry to hear you are struggling. I was similar after graduation - took a job straight from Uni that was a bad fit and got sacked, really struggled for a while
There seem to be stages you have to get through (apologies if you know all this)
Stage 1 is getting shortlisted. It is often a hard filter, often done by junior HR folks or a machine. If you don't have a thing (qualification, key word etc) you don't get through
If you are changing direction (ie Chemistry to BA) then as an employer I would want to see competence in that area - Employers care about (i) competence, can you do the job? (ii) attitude, will you do a good job? (iii) fit, will you be a good part of the team / organisation?
Your Uni should be able to help even after graduation, are they helping?
Sorry but if you are not getting shortlisted then your CV / cover letter isn't good enough, whatever your friends are telling you. FWIW I have multiple CVs depending on the role I am applying to, it is tightly tailored to the application and only contains things relevant to that role
Your studies will have given you lots of transferable skills, so part of the challenge is to get a good narrative around your career choice and how you would meet the 3 needs of employers above.
I work with BAs a lot, it is quite a technical role and very competitive, you will be up against some good candidates with directly relevant qualifications - how will you stand out?
Stage 2 is getting an interview. Usually a human looks at the shortlist and reduces it to a manageable number. Sometimes there will be brief online interviews followed by second interviews. You aren't getting here yet, but when you do having good STAR responses to competency questions etc will be needed
You will want to practice and prepare for this now (if you aren't already) because when you do get an interview you will want to do it well.
I found the whole process frustrating, part of what helped was having a plan - and every day there were things I would be doing:
(i) looking for roles - and not just in the usual places, because the more widely advertised the role the more competition you face
(ii) iterating my application materials, because the more tailored the application the better (usually)
(iii) making applications, again looking to stand out a little
(iv) getting feedback / reviewing CV etc
(v) getting feedback improving interview technique etc
(vi) rehearsing my answers in front of a mirror, or even better video and watching back
(vii) reading around the subject, because you may get a question about something current / topical and it will make you stand out (this happened to me at an interview and really made a difference) - keeps your knowledge current too
Remember, research shows that even the most accurate recruitment process only gets it right about 50% of the time - so it really is a numbers game - but be careful taking a role that isn't right because you feel desperate. My first job after graduation was in manufacturing, it was a really bad fit and I quickly left, which was hard to explain when I went back to the job market
Also remember, about 50% of graduate jobs are not with big organisations. Smaller organisations can be much less "professional" in their selection processes and tend to hire people they like / know / trust. Not sure where you are based but there may be events you can go to, get to know people and then get lucky with a piece of work - FWIW there is a shortage of good BAs in digital design and lots of smaller digital agencies struggle to get good people.
And finally, don't just apply for advertised roles, they are the ones where you will face the most competition. Be proactive, reach out to folks who might have work. Get used to sending speculative letters, get used to using LinkedIn to track down good connections etc