The four-time race winner scored his first podiums as a KTM rider last Sunday at Jerez when he was third in both the sprint and the grand prix.
Miller joined KTM after losing his factory team seat at Ducati to Enea Bastianini, with the Italian brand instead offering him a one-year contract to return to Pramac as a works rider.
Despite what looked like a tough winter for KTM, both Brad Binder – who won the sprint at Jerez – and Miller sit third and fourth in the championship after the Spanish GP.
Earlier this season Miller said he was the most doubted rider on the grid, and once again touched on that at Jerez on Sunday before explaining why he "wanted a new challenge".
"I'm having a ball," he replied when asked about proving critics wrong again.
"I love this stuff, I love it so much. A lot of guys in this championship sit there and complain about the bike they are on, about how other bikes are better.
"If you really want it, go out and do it. It's not hard. I wasn't going to stick around where I was, I wasn't comfortable there and I wanted a new challenge.
"It's called taking a risk on yourself. People in business do it all the time. If you trust in yourself enough, yeah it can come back to bite you in the arse, but I trust in myself enough and my ability and in the people I have working with me.
"We took a risk and it feels mega when it comes off. I can't thank KTM enough for giving me this opportunity, and thank you to the people who doubt us because I love it.
"To have both those bikes on the podium, after so many riders last year were sitting there complaining about how bad this bike was, where is it now?"
Miller led the sprint at Jerez and briefly headed the field in the grand prix, but just faded away from Binder and Francesco Bagnaia in the latter stages of both.
Asked what he needs to finally breach the top step of the podium and join an elite list of riders who scored grand prix victories with three brands, Miller says "it's just time".
"We have a good package, and it's time," he added.
"It's the fourth grand prix and we are slowly but surely arriving. I'm sure we will come to some tracks that are better for us. It's just time."
