In which case I would suggest something along the lines of:
Create a Concatenation of Donor & Feedback Date, say
F2: =A2&":"&C2
copy down for all rows
You can now in theory run a COUNTIF test
D2: =IF(COUNTIF($F$1:$F1,">="&$A2&":"&($B2-10))-COUNTIF($F$1:$F1,">"&$A2&":"&$B2-1),"Yes","No")
copy down as required
It's not great, it will be slow-ish to calculate but it should work (based on your samples)
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