Questions about repayment and filing taxes jointly vs separately

My wife and I got married last year. We are trying to figure out whether to file jointly or separately.

If we file jointly, we get a $2k refund. If we file separately, I end up owing about $1k and she gets a refund of about $1k, essentially zeroing out.

I have been on SAVE forbearance since 2024. In April I will be eligible for a PSLF buy back and file for forgiveness. I will need to buy back about 16 months of payments.

Questions:

• If we file jointly this year, when will it begin affecting my payments?
• How can I calculate my loan payments from filing jointly vs filing separately?

My AGI is $87k and my spouses is $24k. My loan balance is $56k.

Any help is appreciated! Thanks!