Is it possible to edit some .lua files (on my side I mean) so that some subpopulations of biters are much rarer, namely Wasps and Suicides? I'm losing the game as these two are a significant problem to me. The option to not have them is only at startup, so I can't just ask to not have them anymore in an ongoing game, right? I can probably cope with the ones generated, if this is still a solution.

A side remark on Wasps, they have a general issue somehow. Given the turret algorithm, the wasps drones are targeted first because closer, and thus the wasps spiters generating them are not hit in priority...

libs\Constants.lua

if settings.startup["rampantFixed--waspEnemy"].value then
constants.FACTION_SET[#constants.FACTION_SET+1] = {
type = "wasp",
tint = {r=1, g=1, b=0, a=1},
tint2 = {r=0, g=0, b=0, a=1},
acceptRate = {3, 10, 0.1, 0.15},

If you change "acceptRate " values from ..0.1, 0.15} to ..0.01,0.015} , then the probability of this faction appearing with subsequent mutations will decrease by 10 times.

But I must warn you that wasps are one of the most harmless factions. By lowering its probability you will make the game harder

Really? They really pose me a large issue, as my turrets chew a lot of ammo before being able to kill the wasp-spawners.
I saw this section in constant, but it was written as "settings.startup", so I thought it was read at startup and not dynamically?

Thanks for your fast answers anyway, this is very appreciated

Perhaps if the game is heavy at current settings, it is worth lowering the level of enemies in the startup settings:
If set this "World: Ending enemy level (recommended = 5)" value to 4, the biter's health will be greatly reduced, but they will still pose some danger to standard turrets

It feels like one of two situations takes place: either there are few turrets (like 3-4 ), or very heavy pollution

What really helped me was shock turrets, which are basically early electric laser turrets: https://mods.factorio.com/mod/ShockTurret
It's also part of my (Warning, shameless plug) combat/turret modpack: https://mods.factorio.com/mod/Combat-modpack

Thanks, the ShockTurret seems a bit too good to me though, basically it is a replacer of the standard turret, but without ammo?
I have added Alien Loot from Schall, though with a reduced reward, as a way to compensate partially all the expenses I have in ammo.

Electricity is a form of ammo, but I will respect your stance of it not being true ammo. I tried searching for the mod you mentioned, Alien Loot, and am unsure what exactly you're referring to. May I ask for a link?

Alien Loot Economy: https://mods.factorio.com/mod/alien-module
Schall Alien Loot: https://mods.factorio.com/mod/SchallAlienLoot/downloads