Just keep blocking and reporting.
As you say, a number change is the only thing you could do, but that wouldn't guarantee anything as the scammers just input number ranges into auto diallers, so any number could be called at anytime.
@ScamsMulti Unfortunately scam texts are a plague for everyone, with very little to be done about it at present.
Block the numbers and report them free to 7726.
Don’t open any links or enter any information.
O2 advice here:
How to block a number:
Track usage, upgrade and get support with the My O2 appDownload My O2