Good work! When exploring, I also usually start with the later chapters and work my way back, for things like event quests. For permanent content though, I might consider just doing whatever lanes seem easiest with what you have first. By the time you finish them, you may have expanded your roster more, which could make lanes easier that currently seem more difficult.
No I meant do the hardest first and then move backwards. Like 5.2.6>5.2.5 ect
Yes that's how I did it. Gets simpler. Gets the rough stuff away first
5.3 is the most awful hellspawn created by Kabam.