Sports secured their United Counties League Division One status on the final day of the season, in a campaign where they registered just one victory in 2022.
Miller says he will return for the new campaign with a more steely resolve, and expects the same from his charges.
"I was really clear in what I said to my players at the end of last season," the manager revealed.
"I said, 'if you feel that you have given 100 per cent to the club across the season, feel free to have a look and go find another club, if that's what you want'.
"However, if you have not given 100 per cent to the club you need to give something back.
"I am the first one to ask myself that. Did I? No.
"As a stubborn male, that should tell yourself 'that's not good enough - I'll put it right'."
Miller believes his attitude is shared by the dressing room.
He added: "The conversations I've had suggest everyone knows they didn't give 100 per cent.
"If those lads still want to go then that shows me the kind of person they are.
"Ruthless psychology? Absolutely. But that will show me the lads who want to step up and show they're good enough and put right what this club expects."
As Sports struggled to find rhythm in the second half of the campaign, the bottom three slowly closed the gap but were unable to overtake Holwell.
Now Miller is adamant next season must be different.
"It's up to me and the club to right some wrongs next season," he said.
"I would say we were naive in what we did last year. We absolutely underestimated what this league was about after a quite successful period.
"We've learnt a lot. I've learnt a lot. And to have the confidence of the chairman (Graham Lewin) to put things right, it's a great place to be.
"We're more determined than we ever have been, but we're still realistic.
"We're not going to bankroll this club. That's not our ethos."