Welcome to the Forum @Matt_Jaffe and thank you for reaching out!
If you are in a Paid plan you could run an Advanced Search of Tasks add the filter
–> In the Particular Project you want
–> Commented on by : the Project Members
–> Modification date: Within the last X day
(I’m attaching a screenshot to illustrate the steps)
We also have a thread in the #productfeedback category requesting the ability to Sort Task by “Last Comment Date”: Sort Tasks by "Last Comment Date" - #7 by Getz_Pro. If you haven’t yet, I would recommend to upvote it!
I hope this helps! Please let me know if you have any follow-up question!