Cares Act 401K Payback

So I took a 10K hardship withdrawal from my 401k last year as part of the Cares Act allowing me to do so. I filed my taxes last year and got money back based on my intention of putting that 10K back before the allowable 3 years to do so.  My plan was to put it all back by the end of 2021. 

 

My question is, if I come a couple grand short of that repayment by Dec 31 2020 and I pay the balance by the end of January 2022, is that ok? I'm really looking to see if I have to completely pay the 10K back by Dec 31st 2021 or do I have up until I pay my taxes in 2022 (or sooner) to put it all back?

 

Appreciate the feedback in advance!