I have no experience with Samsung's keyboard, but I do like most of the set up of GBoard.
What I don't like is the Google part of GBoard.
The snooping, the spying, that sort of thing.
So I opt to find keyboards that have no internet access and are efficient.
I have two that I use, and modern Android makes it simple to switch between them.
My favorite is very similar to GBoard in how it is set up.
It is called Simple Keyboard.
Simple Keyboard (Simply keyboard and nothing more) -
https://f-droid.org/app/rkr.simplekeyboard.inputmethod
The other one that I use is more elaborate, yet is still small and simple.
It is called Hacker's Keyboard.
Hacker's Keyboard (Four- or five-row soft-keyboard) -
https://f-droid.org/app/org.pocketworkstation.pckeyboard
There is one more that I used to use, and it is called BeHe Keyboard.
It has different options than the other two.
BeHe Keyboard (Hacking & programming keyboard with material design) -
https://f-droid.org/app/com.vlath.keyboard
All three are small enough to have on a single device- to use for different modes (portrait/landscape) and other reasons.