Hi there, me again, if you type "bad reviews Three network" into google the AI overview says...

Three UK has received a significant amount of negative feedback, regarding its mobile and broadband services.
Customer reviews on Which.co.uk ....and Broadband.co.uk....frequently cite poor network reliability, slow speeds,
and inadequate customer service as major concerns.

Specific issues highlighted in reviews include: Network Reliability: Many users report frequent signal drops,
particularly indoors, and in areas with expected good coverage.

Not looked up the two sites it mentions above
Rod Watts