I'm currently in Bali.
They required a vax certificate at the airline check-in, so I showed them my old Pfizer vax papers from over a year ago. They checked very quickly, didn't seem to care it was expired, and just waved me in. You could probably give them a fake paper, the airline desk jockeys wouldn't know the difference.
On arrival in Denpasar, nobody checked anything. No mask requirement, nothing. The only new thing is that post-covid $30 visa on arrival, which has no real purpose other than nickel and diming the white tourists