Congrats on your treble!

Regarding your question on needing to adapt formation; yes, somewhat. As the game gets updates, the formations and/or orders that work best change, so through trial and error, conversations w/ other players, etc... you might get an idea about what works best.

As you level up, there are still plenty of rubbish teams, so promoting is rarely difficult; when it is, its because nordeus is doing a quality based league draw. However, the # of teams decreases so the odds of drawing a server level heavyweight in the CL is higher (same w/ being drawn into a multi-level CL), and tankers will most likely become more prevalent. Watching matches is important if facing one of those elite teams, but against most teams u can get away without attending, even at higher levels.