Recruiting hell - seeking advice

(Shorter post after feedback below)

I’m a recent PhD graduate in economics/business law from a high tier target school applying for jobs within ER/IB/HF in London. I graduated a few months ago. I have done several mistakes along the way and lost several opportunities due to being inexperienced about the job market and building relationships. I will give examples of my f ups!

I got my CV polished by a recently retired MD at a BB who I was introduced to. I mismanaged this relationship due to inexperience (I cringe sometimes thinking of my actions, the shift from academia to banking mannerisms took some practice). Come December and lots of rejections. One first round interview (ops role at one of the largest HFs) and another second round interview with a large MF manager, but messed both up. December was the time that I learned several lessons.

I networked my way into a monumental HF! And boy did it work! (think Millennium, Citadel, DE Shaw). I stopped applying for jobs and focused on several rounds of networking and interviews at this HF. Everyone was so friendly and I literally hit it off with every single person I spoke to there. Had multiple rounds of interviews, passed all, including with most senior person. I thought, wow, okay, it's mine. Come final interview with hiring manager, he absolutely hated my guts for no professional reason. This was all in January. I was shattered but then I decided to brush off this defeat as a victory in the right direction.

So I worked on myself and my interview skills. In February, after recovering from that hard blow, I decided enough was enough Cold emails, job applications, reaching out to my network, following up, you name it... I got exactly two referrals out of all this (one for BB and the other EB but both for IB this time) and maybe 1-2 informational phone calls a week. The majority of cold emails don't even get responses (my success rate is around 7%).

Market is brutal and recruitment literally feels like hell. I send on average 15 emails to both alum and non-alum a day and get around one response, not always a helpful one. Is there anything else I should be doing? If you have any advice please hmu in the comment section or DMs.