Deep Rock Galactic

Honestly, rank doesn't really matter all that much in DRG. Ranks 1-25 get all the standard character unlocks, then you do a promotion assignment which resets your rank to 1, but you keep all unlocks and get an extra active perk slot.

After the first promotion, all further progression is completely independent of rank. Further promotions will give you a couple of new weapon overclocks, but those can also be obtained through normal gameplay via weekly assignments and/or Deep Dives.

So yeah, I wouldn't worry too much about anyone falling behind or racing ahead in rank. Even before the first promotion, the only real difference is that someone might have a few more unlocks that might make them a bit more efficient, but it is absolutely not a barrier to playing together.

I'm an engineer main and I constantly get the most kills in my group of four. The engineer starts off slow but, man-oh-man does it get some amazing weapons, and probably the best grenade in the game. You'll eventually unlock the auto-targeting rifle (LOK-1 Smart Rifle) and the giga-destroyer beam Shard Diffractor which can just absolutely shred bosses. If all of that isn't broken enough, then you also get the shredder swarm grenade, which is absolutely insane. Top that off with two turrets and you can pretty much solo most things.

I didn't play engi for the longest time for similar reasons. After I unlocked some module upgrades I tried the engi again. I consistently get the most kills in the team, unless there is another engi.

My build:

Voltaic: 2-3-1-2-1 with Well Oiled Machine overclock

40mm: 1-2-1-2-2 with Fat Boy

Turret: 1-1-2-2

That is interesting. Are you getting your turret built at a good vantage every bug wave and maintaining it? That would be my only thought.

I started playing drg with my family when they were already around level 10, and it doesn’t really effect the gameplay. It’s cool when everyone is a different class, and someone gets a new unlock and you all get to see it for the first time together.

The only time it might matter is if you play with randoms, a rare minority will assume your skill level from you player level.

Playing with people you know, it really won’t matter at all about the skill level

Rock and stone!

That's odd, all xp and credits are shared by the team. Your individual kills have no effect on it. The only one who would be slightly ahead is the gunner because of xp earned in the tutorial.

A lot of DRG is about finding what your class/build is good at and doing more of that. For example, I almost exclusively play Scout, and one thing I struggle at is swarmers. There are some Scout weapons that cope a bit better with swarmers, but often the best thing I can do is flee in the direction of one of my teammates (probably the driller), and inform them I'm bringing them a gift.

A large part of learning the game is about noticing opportunities like that, especially because there aren't hard and fast rules; it depends on your playstyle and the teams you play with. However, I will say that in the teams I play, engineers often have the highest kill count, so the issue you describe is likely just you finding your footing with the class

Most of the engineer's kills come from their turrets. In a way, they're more your primary than your primary. You want to place them where they have a good line of sight. Keep an eye on the indicator on the right of your screen and refill or recall them if they're running low on ammo. If you break through into a new room, you can set them up near the entry and use them as a fallback location if things get too hot. Occasionally ask yourself "do I know where my turrets are, and are they useful there?" Keeping an eye on the ammo levels are also good for checking whether your turrets are actually shooting at anything, or whether they're poorly placed.

Another thing to bear in mind wrt "right tool for the job" mentality is that as engineer, it can be easy to accidentally waste time and platforms building platform stairs up to high up minerals that would be best left for the scout. Platform any high up minerals and move on. Mining low down minerals is fine, and frees up the scout for getting more of those high up spots that others can't reach. Just remember that a huge part of this game is the synergy between the classes. It can be helpful to switch up the classes every so often to begin to understand what kind of niche the others fulfill. Engineer platforms are good for building short stairs to get out of a small pit, or for covering up holes in the ground in a point defence, or for building a partial bridge over a chasm that's too large to jump over without help.

Oh, and one last thing about engineer is that their starting secondary weapon is rarely used (at least in the people I play with). It's not that it's bad, it's just that the others are pretty cool. There are assignments to unlock additional weapons. Now that I think of it, I'm not that keen on the engineer's starting primary either. The takeaway here is that the different weapons change a lot about how a class feels, so trying other weapons can help. Regardless, most of your kills will probably come from turrets.