I'm confused about the Inherited IRA. If the decedent is not your spouse, the 10 year rule applies.
That's what I thought - but the OP is correct that the age differential being <10 years is a factor.
From Fidelity:
https://www.fidelity.com/learning-center/personal-finance/retirement/non-spouse-IRA
If the original IRA owner died on or after January 1, 2020
The SECURE Act requires beneficiaries to withdraw all assets from an inherited IRA or 401(k) plan by December 31 of the 10th year following the IRA owner's death. Exceptions to the 10-year rule include payments made to an eligible designated beneficiary (a surviving spouse, a minor child of the account owner, a disabled or chronically ill beneficiary, and a beneficiary who is not more than 10 years younger than the original IRA owner or 401(k) participant). These beneficiaries can "stretch" payments over their life expectancy. Discuss the potential tax implications and distribution options of this accelerated withdrawal schedule with your tax advisor.