It's hard with such a map design to guide players in the good lair depending their levels.
The matriarch is a boss fight for level 4 characters but you can run into it really soon without any warning about the danger of the area. This fight can be extremely easy or extremely hard even for level 4 characters, as most "hard" combats in the game. Again, depending the tools you're using the experience can change A LOT, which is not a good thing imo (unbalanced tools = unbalanced difficulty).
An exemple of tips for that fight : you can shove/thunderwave the matriarch in the pit in the middle of the room to OS her... Yes, you can OS the boss with a bonus action.
