OP, I volunteered for an energy charity and there is a huge amount of inaccurate information and downright nonsense about smart meters. There's a whole movement linked to the same people who rant about 5G and chemtrails who are obsessed with smart meters and this stuff drips down.
Smart meters don't send inaccurate reads; they are actually more likely to be accurate than old meters which lose their accuracy over time, hence why they have to be replaced every 10-20 years depending on the meter.
People hit with huge bills after switching are people who didn't send meter reads regularly. When their meter is exchanged, the engineer records the read on the old meter and sends it to the supplier and they bill the use. When people haven't been sending reads, they then get a catch-up bill and blame the smart meter. Ironically, a smart meter would have avoided them needing a catch-up bill in the first place.
The mechanism to cut people off is the same for both smart and traditional meters. For that to happen, someone must be significantly in arrears and have made no efforts to engage with their supplier over a long period of time. If you don't have a smart meter, they will get a warrant and enter your home instead, which is arguably worse. But I never encountered anyone who had been completely cut off, they just switch you to prepay (or force install a prepayment meter with a warrant).
Smart meters allow you access to dynamic pricing tariffs, so if you are someone who can shift energy use outside of peak hours, you ca. save a lot of money. I spent £1 on 40 units the other day, charging the car etc., which would have been £9 on a standard tariff.
Hackers are not interested in when you put the kettle on, and a smart meter can't tell individual device usage anyway, just overall power draw.