BC for United, as a developer is a long way away, if ever. Some examples, they lack organisational readiness, i.e IT capability, data availability. There will likely be external resistance, i.e. stakeholders (including upstream integration), GDPR issues, lack of external commitment, there is no competitive pressure.
Finances/player contracts: There are some interesting article written by Professor Christian Catalini of MIT who suggests near real time financial information can be shared with stakeholders (that could include contracts, integrating into AI can create performance based payments). ACCA have started training BC to professionals. Ultimately, why would management or even players want to publish that information on the BC?
Fan engagement: Gamification for fan experience isn't ready. I was at an Academic conference on Blockchain last week, one presenter asked how many "knowledgeable" attendees used BRAVE Browser, only 2 people in the audience. Another asked who was using the Metaverse (those that don't know the metaverse can be built on the BC). The metaverse increases barriers rather than decreasing barriers i.e it takes more time and it's not inclusive. While i know those are only two examples. I'll add, end users cite, trust, risk, awareness, speed, knowledge, usefulness, questioning the value and doing what is socially normal (waiting for others)/subjective norms.
There is probably greater use value for BC with an FA/UEFA based system with BC folks for clubs.