While you could replace out your bad logic board for a new one and that new one could have more storage. You must replace it with the same generation and features (Cellar or WiFi only).
If this is your first time I must warn you opening up an iPad is not easy and many people damage them in the process (very difficult to open). You'll need the proper tools and lots of patience.
Look though the iPad questions posted here just a little. Then decide if you want to do this your self or let Apple fix it, then sell it and get a new one with more storage.
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