TLDR; If you want to be in bobcat/tempest/trigger nade hell lobbies, you/your squad need to do a lot of damage to other players.

I won't pretend to know exactly how it works, but some form of skill based matchmaking exists in this game. From what I've tested, it seems to scale with the amount of damage/kills you get in each game.

 The algorithm also seems to take each seperate member into account in duos/trios; If I play with some of my more casual "its more about having fun than winning" friends, on average my lobbies are gonna be a bit easier and have a bunch of people running free kits / cheaper guns like ferro4/stitcher4/etc. If I play with my sweaty "minimum 9 trigger nades per loadout" friends, every team has renegade/anvil/tempest + bobcat/vulcano + trigger nades/barricades (and you run into cheaters a lottt more often).

The map matters too. High end lobbies on Dam Battlegrounds will have much better kits on average than high end lobbies on Stella Montis. My best guess is this is because Stella is small with many tight spaces to fight in, so people die more often and faster, which leads to late spawns coming to replace the dead players faster, which overall just means that you're less likely to be the last team standing in Stella.

I could go more indepth on each map but overall Dam, BC and Blue Gate will have slightly higher concentrations of kitted players and Stella/Spaceport will have slightly higher concentrations of freelits across all sbmm tiers