Although i find the game to be super forgiving for how much ammo and money it gives you, if you are struggling with it and you are sure you want to ruin the game for yourself then here is how to do it.

On any bench you can reset your weapons cores for $5000.
Just like Resident Evil 4 this game also reloads your ammo (and health) if you upgrade that stat... so upgrading capacity of the weapon will also refill it and upgrading the health of the suit will refill your health. Which is why you might want to walk around with near empty mag and near zero health until you reach a bench...

There is only one weapon which has secondary attack that wont waste your ammo if it didn't hit a target : that weapon is PULSE RIFLE (also my favorite default weapon).

So to do this you will want around 12 unused cores ideally but can have less (not that hard to stack them even on new game), you'll need 5000$ and a pulse rifle.

Do this like a robot
1. shoot secondary with pulse rifle until you are out of ammo
2. upgrade its capacity, get free ammo and repeat step #1 until you run out of slots to upgrade
3. reset pulse rifle cores and repeat from step #1

Yes its bit annoying, but this practically gives you infinite money which gives you infinite purchasing power!!!