Vodafone here. Your phone contract on EE doesn't allow for beta as it isn't approved by EE.
Vodafone and many others do the same however they is loop holes but it involves pre-ordering. When I pre-ordered my Galaxy S25 Ultra it went out of stock so they needed to ship in a new stock and immediately get one sent out to me.
By pure luck they shipped me a completely unlocked version allowing me to access the beta software.