The 10-year rule does not apply because your sister died before 2020.
If your sister died before her required beginning date for RMDs, the 5-year rule applies and the IRA must be distributed by the end of 2023. If your sister died after her required beginning date for RMDs, annual RMDs are required based on your sister's age in 2018, reduced by 1 for each subsequent year. However, RMDs were waived for 2020.
It's not clear what you mean by "the IRA funds were recently distributed." As fanfare pointed out, a non-spouse beneficiary is not permitted to roll over a distribution. If what you mean is that an inherited IRA was recently established in the name of the estate and then assigned out of the estate to an estate beneficiary, that would be fine, but it doesn't change the minimum distribution requirements.
