I am confused by your question.
For IEC 60601-1-11 specifically, the 2015 standard plus the 2020 amendment is the current version. The European standard (EN 60601-1-11) is identical to the International standard. The endorsement notices tell us so. You don't need to do a 2020 vs 2021 change analysis. The 2020 vs 2021 discrepancy is simply due to how quickly the standards were published by IEC and CENELEC.
What would your gap analysis be against?
If you currently conform to the 2015 standard (without the 2020 amendment), then you will need to review the 2020 amendment and do your gap analysis based on the amendment only.
If you conform to the 2010 version of the standard, then you will need to review the current standard (2015 version plus 2020 amendment) in its totality, and do your gap analysis based on that.
In either case, if the result of your analysis is that you have no gaps against the current standard, then yes, you can declare conformity to it.