Auer, the nephew of DTM chief Gerhard Berger, was left on the sidelines when Mercedes pulled out of the series at the end of 2018, and subsequently joined the B-Max Racing/Motopark team in Super Formula with the support of Red Bull.
He concluded the season ninth in the standings with a best finish of third at Sugo, but decided to pursue a return to the European scene for 2020, ending his Red Bull tie-up.
After being confirmed as a BMW driver for the new season, Auer said the lessons he learned in tackling a different working culture and re-adapting to the needs of a single-seater can help him on his return to the DTM.
“I have gained driving experience through the formula car, through Japan, also through the tracks that were a challenge and through a different tyre," Auer told Motorsport.com.
"But I've also improved technically and perhaps also in my feedback on what my driving style needs. And I have more knowledge of human nature, because in Japan it's already a different challenge when you compare it with Europe, where you can communicate quite normally."
Since Auer left the DTM, the series has transitioned from normally-aspirated V8 engines to Class One-aligned turbocharged inline fours, similar to those used in SUPER GT.
The Austrian pointed out the similarity between these engines and those used in Super Formula, but conceded that in other areas he'll need to adapt quickly.
"The DTM cars have changed compared to 2018, they have become lighter and the aerodynamics are different, but the most important thing is tyre wear," he said.
"The tyres are still the same as they were back then, but I'll certainly have to get up to speed again because you need an understanding of tyres. The warm-up and philosophy are a bit different with the tyres."
Auer added that he had offers to continue in Super Formula, but declined because of the clash between the DTM's Lausitz round and the Autopolis round of Super Formula in May.
"DTM and Super Formula cannot be combined because there are overlaps," he said. "You can't become champion then. So that would have been half the story.
"But even with [Motopark boss] Timo Rumpfkeil, the second year would have been really interesting, because the team had a decent learning curve.
"We've already made our mistakes, and I'm especially convinced of the Motopark team."
Lucas Auer, B-Max Racing Team