This is a longstanding problem with no solution in sight. Some Reddit users argue that if you click on the sidebar instead of arrows on the top, you get the same no-smooth-scroll functionality. I tested this and this is true. But this becomes next to useless when the searched term occurs often and between very few lines, as tapping onto them using the side bar is neither convenient nor practical.
My solution is Kiwi Browser (based on Chromium) and as of version v77.0.3865.92, it has that same classic find-in-page scroll (instantly shows next occurrence instead of scrolling to it). I've been using it because of its support to Chrome Extensions. Firefox for Android also doesn't have this problem either. If the smooth scrolling is a deal breaker you can try these alternatives.
1: Chrome app "find in page" issue
2: scroll-behavior: smooth on Chrome can cause motion sickness issues
3: DISABLE search animation query