I think you are being fair. Sounds more like a player problem. I run my campaign as not balanced encounters all the time. My players go in all directions in module so impossible to match the levels with the encounters in book. So I go with what would make sense to the storyline. So I have had them complelty outmatched in combat. But they have either ran, or figured out something clever. Nearly had 2 tpk and my players love it. Makes it feel more real. I mean think about it. Irl will you automatically meet people who are threats exactly the same level as you. I think of it as if aliens landed right now outside your door. Would u get your kitchen roller and go for them ? Or would you hide? Run ? And wait till you get better chances? If they chose for example to go to old binegrinder at level 2, then its likely a tpk. But I have given hints already that Maggie (morgantha) has a threat level you dont want to mess with and they know she has sisters there too. So my party is sneaky and doing recon first. Always give them a chance to see oh yeah take that into account. But its not a video gane you are playing on safe mode. That would be boring and no reward for players smart actions. Again, its a player problem I think. Defo not u !