Personally, a 3 hour connection in ATH would not bother me.
If my incoming flight is on time, it is a nice place to spend some time, either in an airline lounge, the A3 one is OK, or at the ground floor coffee shop in the Sofitel if you don't have lounge access.
And I have had very tight connections in ATH, coming back from JTR or HER, because of a late departure of the flight, up to 75mn. ATH is a nice airport, but there can be a lot of walking (actually, I was running like hell) involved when connecting there.
So, overall, 3 hours is what I am usually looking for when connecting in ATH. You can probably make the 10:50 to 12:20 connection. For me, it is no longer worth the hassle and the stress involved (ok, I am rather averse to risk as I now schedule 4 hours for a connection in LHR

). And you would not have to spend a day in Athens. Even during the winter season, there are several OA or A3 flights a day.
Enjoy your flights

.