What's decent for primary these days? Not played in a while but reinstalled it this week.
what warbonds do you have? I like the breaker incendiary shotgun from the the steel veterans , the coyote - the new dust devils.warbond, and the disruptor explosive rifle - Democratic Demolition.
if I had to pick one it would be the democratic demolition warbond.
but bear in mind I am no expert and I only have 5 warbonds Inc the freebie.
the beauty of Helldivers is , context dependant, you can make any weapon work so long as you spec your other gear.
ie you need something to close bugholes/end fabricators , and something to take down heavies (incendiary grenade, the explosive pistol and the expendable anti tank is not a bad shout, then with either a laser dog or a personal shield.
that would still leave you without a really heavy rocket launcher .. but the best ones need a backpack. you could use orbital strats for those. it all gets easier if you have a team as you can complement each others loadouts and share.
I am fortunate in that I have 5 other mates who play it,.some of them extensively .. but if not as others have said as a general rule the coop is quite good in this and as long as you don't friendly fire too much most people are happy to let you tag along even if you are not that good.
it can be annoying when they don't reinforce you but I have learned to go with a personal shield and try to look after myself at least for 1st mission then if it goes well consider changing if I stay for another.