I'm relatively new at adjusting pH levels in my brews. As a result, I went the wrong way in my adjustment and produced a very tart red wine. Can I unbottle it and adjust accordingly? And if so, what's your advice on handling that effort?
I would not bother trying to rescue it at this point, you could leave it 6 months as see what happens often the wine will mellow.
But, I would leave it in the bottles and serve it with lemonade or similar, or I would use it to cook meat in, or enrich a sauce, or to mix with olive oil for a salad dressing.
Put it down to experience and try again.