I was thinking that I can get with UA SFO-FRA on E+ on H upgradeable fare and then LH or A3 to ATH, but the connections are horrible, at least 3+ hours.
I don't consider 3-4 hour international connections to be "horrible" by any stretch of the imagination. On the contrary, on connecting international flights I frequently prefer a connection of a few hours to minimize the chance of misconnecting. If that happens, having to wait a few hours doesn't seem so bad when compared to having to wait until the next day.
I'd easily take the E+ (with possible upgrade) vs. being stuck in LH Y (with possible missconnection).