I used to use the GooglePlay plugin previously, it is very easy to use.
Usee the Submit Hiscore action (and define the leaderboard, which you set up in the console) to submit your score.
use action Request hi-scores to fetch the score you want, from the appropriate leaderboard. Window=around you, Top=Highest
the condition On high-score request success to trigger when the scores is fetched.
then you have your score at the expression GooglePlay.HiScoreMyBest
for other people scores you have them at the corresponding index.
If nothing is changed, this is still how it works. Similar to other back ends