This is tricky timeline. If she had to file in February-March 2025, then yes you could divorce first she'd file I-751 with divorce waiver. Technically she could still file I-751 late after divorce, but it's a risky one.
She could file I-751 two weeks before deadline with divorce waiver. It's unlikely she'd get RFE this soon. If divorce finalization is a month away at that point, she'll likely be OK.
I'd say if you guys start divorce ASAP and have it go smooth, she can file I-751 with divorce waiver in December. Worst case if she doesn't have divorce decree then and gets denied, she can refile. It's probably better filing with divorce waiver VS joint filing 3 months before divorce. That looks more like gaming the system to me. One minute you're married, the other one you're not.
I'm not a lawyer and this is not a legal advice.