8.5 year old constantly lying and being deceitful - what are logical consequences??

Long story short, we’ve had issues with our eldest son constantly being sneaky, lying, and deceitful. We catch him at it all the time for the silliest stuff… usually stealing sweets.. and a couple of times nicking a pound or two that’s been lying around on our dressers etc. no matter how many times we talk through it/restrict privileges with him, he keeps doing it?? But he’s also been caught out in some bigger more serious lies like twisting tales that would get people like his teacher or other kids in serious trouble.

Obviously some of this is developmentally normal… but we’re struggling to think of natural/logical consequences that is going to deter him.

How do you all handle it? We’re really struggling with the endless loop of it.