Just got off the phone with my ISP’s tech support and it is NOT MY MODEM!
The tech guy said “omg! You’ve had 400+ dropouts in the last 14 days.”

I said “tell me I didn’t know that!” (but I laughed and was very polite).

Anyway…a tech guy will show up tomorrow to check the actual physical phone lines between my house and the node.

Yay for me!