I have an S10 and love it! The curved screen is an aesthetic feature that I enjoy and have used on other phones before (Honor 8); but it has been difficult to fit screen protectors onto the screen for that reason - not to mention ones that work with the ultrasonic fingerprint sensor. However, I'm using a brand that I enjoy and there are a few other brands that work well!
You'll see a better camera and battery life if you do the jump. However, since the S10 will be about two years old in March, you're looking at less time for regular security updates. However, you'd still get them for a time.
Is getting a Samsung phone very important to you? You can always grab a Pixel 4a or Pixel 5 for an inexpensive price that will have guaranteed security updates for longer time periods, because they are newer. Google is very timely about updates - timelier than Samsung! I've used a Pixel in the past and enjoyed the timelier updates. You'll still get them with Samsung, of course - they may just vary in consistency from month to month. It all depends on your carrier, as well.