Welcome Count Vasquez!

There are two possible reasons for insane power-level squads at low levels. One is that the squad belongs to a whale. A whale is someone who typically spends at least 10000yen (roughly $1000US) on the game per month. They roll the paid gachas and buy flower gems to get as many 5* and 6* girls as possible. The second way (and I speak from experience) is to just log into the game, and not level. How does that work? The original devs on DMM are incredibly, incredibly generous with free goodies and apology gifts. All those 100-year manyu from log-ins? Level the girls, which increases the power level. Also free tickets such as 4* and 3* tickets, both of which have a small chance to give a 5* or 6*. Not to mention boss events, where as long as the person has levelled enough to unlock boss fights (which I've done at level 3 before), you can max out an event 5* and get all her jewelry.

As for your level and power levels, they are completely separate from each other. You can be low level and have a high power level, again, depending on how long you've played the game, and how much you actually level with each log-in. The best way to increase your power level is to have high-level girls. In fact, you may have noticed at first your power level may take a dip after you evolve/bloom a girl. That's because, as you may have noticed, the girl goes back to level 1. Only once she's near her new level cap does she actually become more powerful and add more points to your power level rating. There's also the girls' jewelry, and how much you have upgraded that. Those increase power level as well.

As for the helper squad doing a lot more damage, the important thing to look for there is how often your girls' abilities proc (in other words, the likelihood of them going off). They usually start with a base percentage of something like 20% or 25% chance of happening, and that percentage increases as their skill level does (by using skillblooms or there is a chance to increase it when you upgrade a girl with a duplicate). Also look for girls who do damage to more than one enemy at a time. Once properly raised, they can wipe out a group of pests in one go. As for your blossomed girl, is she high level? And do her skills speak to her being able to take more damage? Some girls have very little defense and health in comparison to others. There are also girls with abilities to evade hits (Monopastrum and Water Lily come to mind). Not all girls have the same strengths and weaknesses. Some are made to be glass cannons (do high damage, but die fast), some are made to take damage (high health and defense, like Edelweiss), and some are balanced. Read up on the wikis about the girls in your team to see what their strengths are, and how they work together in a team.

I'm not a total expert since I'm one of those who are interested more in making up my parties of girls I like, but I do constantly read up about the game because I love learning things. I've been playing for a little over a year now, first on Nutaku, and now I'm finding my feet on DMM since I'm just.. not happy with Nutaku anymore.

Anyway, I really hope this all helps give you some insight!

And, er, sorry for just bombing the thread like this. I've been lurking, but since I don't have a "main" FKG DMM account worth speaking of, I haven't joined in before. ^_^;;