You are going to get answers like 'There is no perfect tactic' and 'it depends on your players' etc.
To be honest I don't think there are any legendary super tactics anymore where you win every league game, and every trophy like there was a few years ago. I would advise you to make a tactic yourself and start with a formation that you like. Then keep working and tweeking the tactic until you have it working well. If you need help along the way, you can share the tactic and instructions on here, and people can give you more specific advice.
This is exactly what I did recently. I just put all of the positions and certain roles that I like to use, and put them all in a 1 formation. Then I started working on player roles I like to use and just continued on from there with the team instructions and certain ways of playing etc. After a few tweeks I now have a tactic that is really good and the game is a joy to play again.
No doubt after my post, someone will just post a link to a tactic and you'll just destroy all teams with it 😄