First, I think your triple crown is an enormous achievement!

I have many feelings about your words, because I joined around the same time, and my team is also at L13 now. It's a 35T team without real world money investment. In 1 season, I tried to tank in halfway but I was not aggressive enough to use illegal formation and strategy. Eventually, my team failed to avoid promotion. As my team did not qualify to play CL in subsequent season, so it was then financially less well off. So be careful to ensure your tank job done.

For at least 3 seasons, my team joined leagues including at least 7 teams which are1 league level higher than mine. Luckily, the largest skill point gap with them was just about 7 or 8 skill points. Probably most of them were not very active. So I could manage to narrow those gaps during the season. It is not easy to play against teams with advantages like signing high quality players. But I still enjoy challenges to compete with stronger teams, provided that I find a probable goal, like promotion or CL qualitying, to play for.

Theoretically, league competition is reasonable because teams with similar qualities (except for teams saved skill points) will join the same league. On ther other hand, I know that even leagues in the same level could have different prize money. So I always assume that if I joined a league with strong opponents, the reward can be higher. This provide slight me extra drive.

I think we play the games for fun. If you feel tired for the competition, it is fine to take time enjoying other things, tank, rest, and then come back with a stronger team.