Possession game is still effective!. Here you have my tactic. It's working very well for me with F.C. Barcelona on season 4.
After trying more "direct" and "vertical" tactics my team started to struggle scoring goals (won many matches 1-0 with a goal by a penalty, or free kick, etc.).
I decided to tweak my downloaded tactic and got a great result.
This is the tactic I tweaked: https://www.fmscout.com/i-352-tiki-taka-press-attack-fm20-tactic.html
Author is Johntra_Volta.
Here is how the tactic looks:
And here you have some results:
When you are two goals ahead, you can either reduce "Tempo" to the lowest possible to have the control of the match (so your rival will have less chances to score you, but you will also struggle to do it), or you can maintain it untouched, assuming a little bit more risk but with great chances to score more goals.
Hope it works for you.
Sorry if I have made any mistake in the text, English is not my first language.