Is a masters worth it and what are my options?

Essentially went to a Uk semi target uni for finance/consilting as its a target for law (Bristol) I got a 2.1 in Law and have A*AA at A-level, straights A's at GCSE. Chose Bristol as for Law its a high target but now I do not want to be a lawyer and regret choosing bristol having had offers at warwick and durham. I graduated in 2022 and am currently at an associate level role (HEO) in the UK civil service where my title is assistant commercial manager in the trade department, i do contract management and procurement. I want to transition into management consulting or any sort of better compensated related role, ive also looked at compliance. My main motivation is compensation, im currently on £38k. I had a tech consulting offer but that was withdrawn due to the economy that guaranteed me £55k-60k after two years. I feel stuck now as i do not intend on remaining in the civil service as at the senior level it takes too long to be promoted and does not pay enough. i want to hit 70-100k before Im 30.

May be worth noting I've had final rounds in the past at the following:

Deloitte (procurement), KPMG (Audit), Newton (consulting), PA consulting, Vendigital (consulting)

I am thinking of doing a generic masters in politics/history at a london uni, i reckon I will get into KCL and UCL and maybe LSE, but these courses cost about 20k and not sure if they will boost my prospects as my academic background i believe is already ok and I will be going for a non-targetted course. Please let me know if i am wrong thanks.