If you don't mind taking a small loss, you can trade it to GameStop to upgrade to a newer model. They appear to be offering $180 + $50 trade credit until next Tuesday .. ($230, if I read correctly).
Try wiping it first. See the video How to Prepare your Switch to Sell.
But they might test it with a random game if it's still messed up. Don't bring in any games with you.
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As a side question, can a Switch system be messed up if updates fill the internal storage? New games have a check in-place for available space .. but updates...
Just an after thought, since the OP says the system started crashing after a Zelda update failed, and the OP mentioned digital games downloads + DLC, without an extra SD memory card. And the factory internal storage is small.
.. perhaps new games can't load because there isn't any room left for new data storage, whether permanent, or temporary. Hence Fortnite not even starting. Wondering if that update overstepped it's permissions because its a 1st party game...