Joshua is on a four-fight winning streak and will become a three-time champion if he defeats Londoner Dubois.
Watford-born Joshua has faced an intense level of scrutiny for the majority of his career but says he never doubted himself after losing a second consecutive fight to Usyk in 2022.
“The only time it’s over for me, at any level, is when I say it is,” Joshua said.
“I don’t believe anyone can tell me enough is enough – I believe I belong at the top.”
After two fights in Saudi, Joshua returns to home soil and will compete in front of at least 90,000 fans at Wembley Stadium, the same venue where he defeated Wladimir Klitschko in an epic bout in 2017.
He is favourite to overcome Dubois but having sparred several rounds together in the past, Joshua says he will not underestimate the champion.
Dubois, 26, beat Filip Hrgovic for the IBF ‘interim’ title on 1 June and was elevated to world champion when Ukrainian Usyk vacated his title.
“He’s got a good mindset, aggressive, good lead hand, good backhand, dips and throws the right and over the top very well and does the basics pretty well as well, he’s a very well-rounded fighter,” Joshua said.