Update: Education store offer has expired
These are the cheapest it has ever been for the S10 line. Requires a corporate account though!
Here are all the devices:
S10e 128gb: $779.35
S10 128gb: $876.85
S10 512gb: $1,104.35
S10+ 128gb: $974.35
S10+ 512gb: $1,201.85
S10+ 1tb: $1,559.35
It's interesting that you're upgrading from a phone first sold in 2016. Seems like you've held on to it a bit longer than the standard 2 years
The S10E or Huawei P30 Pro might be the better choice based on length of ownership. I think from there it's probably preference based. If you're used to Samsung and like it then it's worth going the S10E route. Otherwise if you're keen for something new the Huawei P30 Pro seems to be a decent enough alternative. I myself got the S10 from the 30% off and my main draw to it over the S10E was the display and battery life. Been excellent so far.
I think that the Pixel 3A might not hold up in a year+ but just my thoughts