Staying store admin while new owner takes over

I am about to sell my shopify store to an overseas acquisitions equity firm. The deal includes vendor financing the company for 18 months, so a deposit and then monthly payments until balance paid. Contract stipulates that the store is not theirs until fully paid, and i hold rights to domain until then. My solicitor has asked if there is a way to ensure i hold rights to the shopify store until that time, and im curious logistically if anyone knows best way to do this. I thought about staying the store admin, but this would prevent them from installing apps, would it not? I can see an option to ‘install app charges’ for user privileges but can not check it no matter what I do. Thank you

Yes I did