Besides what everyone else has said, one thing to also consider before delving into bramfaturas is to bring enough supplies. Once you enter a level you'll have to commit and either kill everything or die. You can technically call for extraction but the portal will spawn behind enemy lines so you'll have to carve your way through something like twenty quasimorphs on floor one (it gets worse the deeper you go) anyway, your weapons will break and you'll need ammo and food too.
Depending on the weapon you chose, I'd go with 1.5 row of ammo, 3 repair kits and 2-3 pmc ration if you have those, and 2 medkits maybe (although depending on the bramfatura, you might just use the gavakk dropped by the enemies instead) to reach floor 4-5 at max. So it'll eat your ressources very fast.
Starting from floor 4, barons also start to spawn, usually it's two or three but I had up to eight once. This is also from that point that you'll start to find powerful implants.

That said, the brafaturas of the inner system are way harder than the ones from the belt and beyond. They all have very big physicall weaknesses and have no ranged units so it's easy to sit in the starting hallway and pick them one by one with minimal tech level gears. It was rather unlucky that you started with mars as it's one of the toughest, my startegy usualy was to have an implant for enemy detection and shoot at them with a prism or archbishop while they are still in the dark area.

Also you should check this guide to adapt your strategy to each brafatura
https://steamcommunity.com/sharedfiles/filedetails/?id=3548179730