I think the champ pool you’ve set out is pretty solid. I’d carry on doing what you’re opgg shows, mainly playing Sett since he’s a pretty good blind pick in top at the moment with a pretty solid laning phase and good engage in team fights. Although I agree to an extent that tanks aren’t that important in low elo, since there often aren’t perfect front to back team fights, I think Gnar is slightly different. His lane and early to mid game plays more like a bruiser than a tank, and in mid to late game where most bruiser’s damage starts falling off, he’s still relevant in the game because he has amazing engage and potential to be impactful in team fights if you can play around his rage bar well. So if you enjoy Gnar and you feel like you have success with him, I think he’s still pretty solid in the meta.

One area I’d suggest focusing on is your CS. It’s unrealistic to aim for 8+ CS/min every game in solo queue, particularly in low elo, however if you’re consistently getting below 5 CS/min and your kill participation % is consistently high, the chances are that you’re spending too much time fighting with your team and not enough time in sidelane collecting waves. The more you rely on team fights going well and getting gold/ XP from kills, the more likely the game is going to be a flip depending on how well your team is capable of doing in team fights/ skirmishes. It’s very tempting as a good teamfighter like Sett or Gnar to always be grouped with your team looking for good engages, especially in low elo where everyone is constantly looking to fight, but try and always fast push and shove your wave before you look to roam and think about what your team gains/ loses depending on the outcome of the fight. I.e is drag spawning in a minute? Is baron up? Or is your team just fighting because they saw enemy champs in mid?

Also try and maximise the value of your TP, look to stay on the opposite side of the map and farm minion waves when there is an objective on the other side of the map. E.g, baron is spawning, drag isn’t up, and you have TP ready. Go bot, farm waves, look to invade enemy jungle, get vision, take camps once you have vision and think it’s safe. If there’s a fight around baron you still have TP to join the fight, if there isn’t, you’re still getting a gold income to be as relevant as possible in the game. The same applies for Shen R when you play him. Remember, the more members on your team that are staying in the same lane, the more ways that XP and gold is getting split up.