## What are all pairs $(R,M)$ of a ring $R$ and a left $R$-module $M$ such that all endomorphisms of $M$ are scalar multiple of $\text{id}_M$?

I was playing with some endomorphism rings and got curious whether a classification of all (not necessarily unitary) module $$M$$ over a (not necessarily unital) ring $$R$$ such that for every $$R$$-module homomorphism $$\varphi:M\to M$$, there exists $$r\in R$$ such that $$\varphi(x)=r\cdot x$$ for all $$x\in M$$. I know that it means $$\text{End}_R(M)\cong R/\text{Ann}_R(M)$$ but I can’t make any interesting conclusion from this. In the case that $$R$$ is a division ring and $$M$$ is an $$R$$-vector space, then it is obvious that $$M$$ must be at most one-dimensional. Could you please give me some references if there are any studies regarding this question?