Future captain me here with an answer! Apparently this tap on word + cursor placement thing is not managed by the OS but by the keyboard app you use.
So here's a config that works great:
- Use Swiftkey keyboard.
The problem is Swiftkey sucks big time:
- it doesn't solve the question's problem, which is a crime against human competence.
- it always inserts a space after a period, making urls or "e.g." impossible to write.
- it doesn't let you capitalize the next letter after space only after pressing space after the dot, ie if you weren't writing a url.
- you keep accidentally tapping on dot instead of space while typing quickly and you can't change the layout.
The following steps will de-suck Swiftkey and solve all your keyboard problems:
- Root your device. Don't listen to your "parents". Best security is on rooted phones unless you're really unsavvy in which case it's just as bad as not rooting. (but for this you can unroot afterwards)
- If you're concerned about Swiftkey privacy now you can install a firewall that blocks or monitors its internet access.
- Install the Android Xposed Framework and Xposed Installer (may not work (yet) on the latest version(s) of android) (needs root, but you can unroot after the install if you must).
- Download and install the "Exi for Swiftkey" Xposed module (github).
Just crawl through Exi's settings and you'll find the right checkboxes. It magically changes swiftkey's tap on words and other behaviours.