I'm in a bad situation

I'm in a tough spot right now. I'm 19 years old and want to get back into education.

I left secondary school with only Level 1 BTECs because I didn’t pass English and Maths on my first try, and I didn’t do well in my GCSEs. I enrolled in a City & Guilds Level 2 course at college but dropped out due to mental health issues. After that, I wasn’t sure what to do, so I got a retail job. This was my third time working in retail, but I stayed for a year and a half. Unfortunately, I recently had a work-related accident, resulting in a Grade 2 muscle strain and a damaged lower back. This incident has made me reassess my situation, and I’ve realized (a bit late) that I need to focus on education to get a professional job.

I want to go to university to study Automotive Engineering because I’ve always loved performance cars. But to get there, I need a BTEC Level 3 certificate in an engineering field, preferably in vehicles. The problem is, now that I’m 19, many courses are closed, and the ones I’ve tried to apply for have said that there’s a low chance of getting an interview. I don’t want to spend years doing Level 2 and 3 at college only to repeat a year in university. Plus, if I can’t even get into a Level 2 course this year, it feels like I’m just losing more time.

On top of that, my osteopath has advised me to take a break from working in retail for a few months to recover from my injury.

I’m really not sure what to do next, and it’s stressing me out. I don’t usually ask for advice on forums, but I’m at a loss, so if anyone has suggestions, I’d really appreciate it.

You say you "I left secondary school with only Level 1 BTEC". What subject was that in?
You also say "I didn’t pass English and Maths on my first try". Does the phrase "first try" suggest that there was a second try? Did you get your GCSE English and Maths in the end?
It's understandable that you want to avoid wasting any further time. However, you need to consider that most students study GCSEs for two years and then A levels or Level 3 BTECs for two year before heading to uni. So, unless you plan to accelerate this timeline, you may have several more years of pre-uni education ahead of you.
Even if you managed to embark on a Level 3 BTEC course, are you really ready for that, given that you didn't pass any GCSEs (if I've understood you correctly) and didn't complete your Level 2 City & Guilds course at college?
A more realistic aim, I'd have thought, would be to focus on your GCSE Maths and English - not just because those will be useful generally, but because that will teach you skills which will be essential in the education which follows.
Have you looked at Access to Higher Education (Access to HE) courses at all? Many universities accept them, and they might be more appropriate for the situation you find yourself in. If you haven't come across them, do a little research on them and see what you think.

Apologies, I should have explained things in more detail. I earned Level 1 BTECs in Health and Social Care, Public Services, and Travel and Tourism. I did pass some GCSEs, including Physics, DT, and Computer Science. I also passed English on my second attempt, but I missed the mark in Maths by just a few points. I plan to retake Maths while completing my Level 2 qualification.
I’ve spoken to a senior careers advisor at a grammar school, and they advised me to get the Level 3 qualification, as that’s the only thing I’m missing to apply for university. I’ve also contacted several universities, and they’ve confirmed that all I need is a Level 3 qualification to be eligible for admission. Time is important to me because I’m planning to leave the UK as soon as possible due to personal reasons.