So, I have this world that was perfectly at peace, until the party came around. Now, It's basically MWW (magical world war). And my players are looking foward to some trench warfare in dnd.
Why trench warfare? Because mold earth is a cantrip and it is always better to have cover. I have a couple of basic ideas.
The bullet points are:
Scrolls, rare magic items and more than lv5 npcs are hard to come by, because they are strategical game changers froom both sides.
There is gunpowder in the world and the spell detect traps actually detects traps (location of all in an area), so, landmines are a thing.
Someone as figured out ballista machine guns, so charging is unadvised.
I'm looking for tactics and general suggestions.
I would watch Tanya the evil for creative inspiration. You pretty much just described the show.
As far as tactics, I would watch a lot of YouTube videos on mob tactics in DnD. Mob tactics can be really hard to get right for the specific context of scenario, so you'll have to watch a few videos before finding a method that works for you. I've personally found a mix of roll together and individual plays can be good, like squad based turns pretty much. But that was for a Melee war scenario I did. IDK how to make it work when long range is something everyone on the battlefield has.
Maybe look into how Warhammer 40k is played, could give some inspiration for home brew rules to make the combat smoother.