EE is excellent at giving good service through their 5g compatible sim cards. They swiftly helped me to get started. All the negative reviews have either incurred an issue which is their own fault, purchased a cheap broadband and then complained that it was not working as it should, or had somehow not read their contract.
Either way, EE customer service is top notch. They are responsive, helpful, and knowledgeable about what they are doing.
If you want a reliable service provider, go to EE.