Hello,
For now you can only freeze columns to the left from the column you choose, so unfortunately there is no way to freeze column B and C without freezing column A as well. You can refer to this guide to see how freeze functionality works: Freezing rows and columns - ONLYOFFICE
I see… is it possible to add such a functionality? At the end I could simulate it by hiding column A, but it would be useful to have this functionality.