Consider having the data from your website pulled into a Table A in Base A, and never touching it. Table A might be the only table in Base A. You can Sync that table to another base (Base B). Base B will likely have more tables to hold other data.
You’ll be able to add as many columns as you’d like to Table B in Base B, and all the columns shared from Table A won’t be editable. If you have a Pro account, the data from Table A could be synced to Table B at regular intervals.
Learn more about Syncing tables: