The OnePlus 7 Pro is the highest-end phone the company has ever made, while the Galaxy S10e is ostensibly the "budget" phone of the Galaxy S10 lineup. But the prices are close, and that makes this an interesting comparison.
The latest Galaxy S20 leaks don't paint an affordable picture: a €999 starting price for the Galaxy S20 (with 5G), up to €1349 for the Galaxy S20 Ultra. That's expensive, but Samsung won't be alone in 2020; all flagships are going to be expensive.
The upgrade to a Galaxy S10 or S10+ is worth it, but you'll pay quite a bit for the privilege. Whether you make the move depends on how much you value relatively small upgrades in battery life, display quality, camera and various little features.
"Active Edge" lets you squeeze your phone to launch Google Assistant or silence incoming calls and notifications. It's a pretty neat trick that accomplishes a simple set of features; and you can just as easily turn it off.
The best part of the Pixel 4a is likely to be the same as the Pixel 3a: getting the basics done incredibly well, pairing it with an awesome camera and slick Google software, and doing it at a great price.