Good morning Lukas,
To remove your personal account from Windows, open settings and navigate to Accounts > Email & accounts. Under the section for accounts used by other apps, select the personal account and choose "remove". After that, add your business account by selecting Add a workplace or school account and following the authentication prompts. If the personal account is currently used for Windows sign-in, you must first switch to a local account via Settings > Accounts > Your info by selecting "Sign in with a local account instead" before proceeding with removal.
I hope you are clear with the information. Should you have any more questions, feel free to leave a message. It's really appreciated of you to accept the answer to help build the community by sharing your experience with the issue. Thanks!
VP