In my setting a large city state has been cut off from the rest of civilization through the appearance of a large alien forest that sprouted up during the medieval times and cut off the city state from the rest of the world. The forest's main goal for the purposes of the story is to contain the city state, so any humans that try to cross or fly over the forest are met w/ essentially a wide array of monsters from the hyper fast, to humanoid sized, to large scaled beasts. At present the city state has technology ranging from WW1 up to the interwar period.
I am trying to arm a special squad of soldiers whose goal is to explore the forests w/ weapons that they can use to counter a wide variety of threats. They are specialized in high mobility/ fire and maneuvering.
What shoulder mounted infantry weaponry would allow them to deal with a wide variety of targets that vary in size that fit within a diesel punk setting or period of technology up to right before the start of WW2. I am fine with a small amount of handwavium/unobtanium so long as it's grounded in some basic reality/physics.
The main issue I have is having a shoulder mounted weapon that can deliver an effective punch, but not be ridiculously heavy to lug around the battlefield in a forest for a squad of soldiers who have to be moving constantly since the battlefield for them is 360° rather than an established frontline. Ideally it would also be something that would be attached to a shoulder rig so that it can be fired while they are on the move via a remote trigger/switch.
The heaviest and largest opponent they would end up facing would be a large organism like say a minotaur that is tall and heavily armored up to a point before square cube law comes in and makes it unreasonable for the organism to be combat effective.
Edit Upon seeing the answers so far, I am going to advance the tech into the realm of WW2 all the way up to the end of it. It appears the limitations of WW1 and interwar are simply just to much to handle. The purpose of this weapon is to augment/add an extra layer of firesupport and flexibility. They will still be able to carry normal fire arms. This is just a way for them to rapidly deploy a weapons platform while on the move to help them.