I was an F-1 student/OPT until DEC 2021. I'm in my home country waiting for my permanent residency to get approved. I'm married to a US citizen. How do I file my taxes?

A lot depends.  If you are filing a joint return with your spouse who is a US resident you can file a joint return and be treated as a US resident for tax purposes.  This means your income worldwide would need to be included on the return.

If you choose to file separate from your spouse, you would need to contact Sprintax.com for the best advice on filing as a resident or non resident as TurboTax does not handle nonresident returns 

So my wife ( a US citizen) already filed her taxes, and she filled them separately. We have been doing this because I was a non-resident alien. I used Sprintax in the past, so this year I was doing the same but they told me that for tax purposes I am considered a "US resident". I contacted them to have a further explanation on this but they did not give more clarity on this. They just told me that my situation can not be assisted by Sprintax, and since according to them I am a "US resident" I should deal with Turbo Tax.  Thank you for the advice!   

So if your conversation with them determined you were a US Resident for tax purposes, then yes, you are good to use TurboTax to file a form 1040 as a US Resident.

Your one other option is for your wife to amend her return and you file a joint return.