Vettel, who won all four of his F1 titles in consecutive years from 2010 to 2013 while with Red Bull, has enjoyed much less success since joining the Scuderia in 2015.
This season in particular has been disappointing for the German, who has retired from two Grands Prix and failed to finish higher than sixth in 10 races.
Next year he will join Racing Point, who will have rebranded as Aston Martin by the time the 33-year-old arrives.
“There’s things that I should have done better, things I probably should have seen earlier, fights I shouldn’t have picked,” Vettel said on the Beyond the Grid podcast, reflecting on his time with Ferrari. “But then I think everything that happened brought me to where I am now.
“I’m generally not talking about stuff happens on the track. Losing the car in Hockenheim [in 2018] in half-wet, half-dry conditions, many people point that one out as a low point.
“But I’m not talking about things like that, more about what’s going on. If I am fair, and harsh, then I have failed. Were there reasons? Probably yes. But I don’t accept them as excuses.”
Vettel acknowledged that certain battles “weren't worth fighting,” but added: “Then again, part of it is probably my nature and it was natural to do so.
“I love racing and I’m looking forward to go racing. I don’t regret the last years and I learned a lot in my time with Ferrari – a different team, a different culture – but yes, certainly Ferrari is a special team in many ways and I guess where I’m going will be different. I'm looking forward to it.”
There are still seven Grands Prix remaining this season, which has been shorted due to the coronavirus pandemic, and Vettel sits 13th in the standings out of 20 drivers.
Ferrari, meanwhile, are sixth out of 10 teams in the constructor standings.