I couldn’t agree more with Melissa. I hope you decide to introduce incremental analysis.
As a new (and willing to pay) user of SonarCloud, I have to onboard my existing code repositories. Some of these repositories host vast code bases and some are legacy. If I were to implement SonarCloud today, it would report on the enormous amount of bugs, vulnerabilities, and code smells per PR. In fact, there would be so many of these historical issues, that it would be impossible to identify any new issues. This effectively renders SonarCloud useless and provides no benefit to my organization.
Is there a recommended way to solve this? Going back and fixing historical issues is simply not an option.