I passed it after about 7 tries with no special tricks or boosters. 3 stars and 11352 points. The French video for this level shows you the strategy.
Thanks for the suggestion, Allan. I had Googled "Alphabetty 710" to find it. Here is the link:
1. If after 5 moves you have less than 20 bubbles, abandon and start again. You need a lot of space right at the start or you won't finish. Make long words (5, 6 or more letters).
2. If you run out of lives, relax and meditate.
Alphabetty is my favorite game of all time. It mixes knowledge and strategy for a unique brain challenge that is loads of fun.
The Alphabetty community is international, and we all have something in common: the love of the game.
I have the counter too. I play on my Android phone, a Galaxy S6 edge+. It's funny to see that I've been playing for 3 days. I think it's more like 3 years. I've passed 810 also. Waiting for more. Love this game!
After a dozen or so tries, I decided to use a crown (which actually gives you 3 crowns) that I'd saved from the noontime wheel spin. That was the secret for me to beat this level, including a decent board. Not such a terrible level after all.