Help getting financial aid as I'm now unable to work due to autism (UK England)

Hey everyone! I (21F) have been diagnosed with autism since I was 10. I'm a Level 2 support needs autistic that struggles with extreme social anxiety and agoraphobia due to my autism.

Since 17 I've been in the workforce in customer service roles. The only reason I was able to push through is because it was relief from my abusive parents, who forced me to get a job and ignore all of my support needs as "Autism isn't an excuse to not be an adult". They've been financially emotionally and physically abusive my entire life and it led to a big repression of my neurodivergency, so I passed as L1 support needs.

When I went to university the abuse continued, on top of schooling and financial pressures. I needed to work to survive and I pushed myself into severe burnout by the end of my second year of uni.

At the beginning of this year, thanks to support from my partner both emotionally and financially I quit my last customer service position and cut my parents out of my life. A month ago I moved in with said partner (21Nb) after I moved out of my uni accommodation, where I've been bullied and socially isolated by my peers. Now I'm in a safe environment I've crashed in numerous ways and my autism has finally began to unmask and be more noticeable. Sensory issues have gotten worse, I struggle to do most things unaccompanied besides using the toilet or getting dressed, etc.

I can't work anymore. And I not only feel like a failure for it as someone who WANTS to work but also it means I'm struggling financially.

I'm claiming universal credit but I made the commitments before this big regression took place. I also want to apply for PIP but I have no idea where to even begin. I don't know how to sort out my universal credit situation especially as I'm still paying off an advance payment I took when I was between jobs in june-august). I don't know how to start PIP as one of my biggest hurdles is I'm unable to do phone calls due to my autism. I also am scared that the severity of my autism now it's becoming unmasked won't be believed, as when I was constantly suppressing myself I was employed.

I just need guidance. A thorough plan, scripts I and my partner can use to advocate for myself, literally anything. I'm just at a complete loss. If any extra information is needed ask away

Thank you!