There are ways to continue Young Sheldon beyond season 7.
When it started, both Sheldon and Missy were nine years old, and it primarily revolved around the boy genius. Over the years, however, it has diversified its storytelling, focusing more on the rest of the Cooper family.
Since Sheldon is no longer the central character of the series, and there's already enough interest in the rest of the Cooper family, CBS can just spin it off to a show that focuses on the rest of the clan. So The Big Bang Theory prequel can move forward with Sheldon's relocation to California, but the narrative continues in Medford.
After Young Sheldon fixed a TBBT plot hole about George's affair, it will likely happen in season 7. However, instead of rushing the following series of events, it could fully tackle its ramifications on Sheldon's relationship with his dad until he relocates to California. Then, save George's death in the potential season 8 just to space out these big changes.
