Unable to verify identity

Dongcopter

Hello, I'm not sure if I'm posting this in the right section so please do correct me if I'm mistaken. My problem is exactly as in the title - I cannot confirm my identity ANYWHERE.
My problems started back in 2016, I've been trying to open many bank accounts to no avail, because they couldn't confirm my identity. I left UK for a couple months and tried again, but the result was the same, so I settled for Monese instead. This was supposed to be a temporary solution, but now I'm kind of stuck with it.
Besides that, I can't get a credit check. At first i thought this may be because I don't really have a credit history as I'm only 20, but this is not the case. I can't prove I am who I am. The only one I was able to get was the one from CheckMyFile, but this one is pretty much irrelevant. I insert the same data everywhere, but I can't be identified anywhere. GOV.UK doesn't work for me, as my activation code has expired and I can't get a new one because reasons.
I wasn't born in the UK, I come from Poland so I thought that this may be the problem. Well, not really. My girlfriend arrived here in September, and she was able to open a bank account in Barclays straight away, and I just set up her Experian account. It works for her, even though she's only been here for 6 months, and she's not on the electoral register yet.
I changed addresses quite a lot (3 different UK addresses since 2013), as I was living in and out of UK since 2013 for several reasons. Can it be that they can't identify me just because I moved a lot? To be honest it is quite infuriating that I can't open a bank account or get a credit card, even though I have a steady job, permanent address, I am on the electoral registry and I do have my NIN.
Is there a specific phone number I can call and sort this out? Am I alone or are there more people that actually face the same problem?
Sorry for the long text, any help would be appreciated.