Flip your position, if you had an extra $14k (or more) lying around, would you buy that card with it?
Not a card collector, but I would sell for a few reasons:
Very limited demand and small market. It's not a card I believe a lot of people were out there chasing. When I was a kid, everybody wanted the Michael Jordan, Jose Canseco, Ken Griffey, Jr, Shaquille O'Neal rookie cards. I don't know what the kids want now, but I'm guessing it's the LeBron, Steph, Luka, Wembanyama rookie cards. Your card is cool because it's rare and valuable, but it's not the card every collector wants (or even knows exists). One's been sitting on eBay (for $33k) for over 2 months without a buyer. And then there's a very small market of people willing to spend 5 figures on a card, and the market is really minuscule when you remove the speculators.
A lot of substitutes are available. This goes back to nobody really chasing this card, if you want a rare card of all time greats, well there's different Jordan/Bird/Magic cards you could get, like
this one or
this one, or get a
Jordan/Magic/Dr. J card instead. Or even better a
Jordan/Bird/Magic/Lebron one or a
Jordan/Bird/Magic/Dr. J/LeBron one. Or a
Bird/Magic/LeBron/Dr. J one. Or a different
Bird/Magic/LeBron/Dr. J one. Or a
Jordan/Bird one. Or a
Magic/Bird one, etc. Or forget autos, what if we go with game worn jersey patch cards, there's
Jordan/Bird/Wilt/Kareem, or
Jordan/Bird/Magic/Wilt/Shaq/Kobe/LeBron/Dr. J/Duncan, or
Jordan/Kobe or
Bird/Kobe/Gervin/David Robinson, etc. There's so many combos of these auto and jersey cards out there, and more are coming out all the time, if there's not a Bird/Pierce/Tatum or Bird/Jokic/Luka auto card out yet, there probably will be one some day.
Everyone here is still alive. Upper Deck (or whoever) can pump another round of Jordan/Magic/Bird cards out at any time. Just look how many combos I referenced above, the card makers are not going to stop that gravy train. Though a newer interesting wrinkle is exclusive contracts, as Jordan I believe is still signed with Upper Deck, while guys like LeBron and Wemby are now signed with Fanatics, so some new dream combos may have to wait.
There's a shrinking target demographic. Let's face it, we're all pretty much middle aged men here in our 40s and 50s. We're the guys who grew up idolizing Bird/Magic/Jordan and have disposable income. But the pool of us is getting smaller every day. We're selling our collections, and/or we chased the memories of our youth in some other way (I bought a USS Flagg and Terror Drome lol), or we no longer have disposable income, and we're unfortunately dying. There's not really a new batch of Jordan/Bird/Magic fans coming up. (Though on the plus side, a lot of us are in our peak earning years with maximum disposable incomes). There is a new batch of card collectors coming up, but they'd mostly be interested in your card for speculation purposes, and they'd probably rather go for one of the Jordan/Kobe/LeBron auto cards.
If it was me, I'd sell, and be happy I made a minimum of 15x on an investment ($20k-$30k may even be attainable here).
Of course that leads to what would you do with the money? It doesn't sound like you need the money. So you can invest it or blow it (or do something boring like remodel the guest bathroom, yawn). I'd probably take $1k-$2k buy myself a new toy I don't need. Invest half of the remaining in a low cost index fund, and with the rest take the family on a 5-star vacation.