That's not the problem I meant.

Matrix has an odd internal data representation of rooms that results in very high CPU, memory and storage use when joining large public rooms on other servers like matrix.org.

If you plan to mostly use it for internal communication and only have outside users join rooms on your server then the system requirements are relatively modest.

But usually there is always at least one user that tries joining large outside rooms and that tends to crash matrix servers on low end VPS pretty hard.

But if you are only looking for an internal chat system there are actually better options than Matrix.