Oh I've definitely both seen this in others and dealt with it a ton in my own work! It's usually called 'SameFace Syndrome' in most of the circles I interact with. It's always hard to juggle having a distinct way of drawing things and also diversifying withing your set 'style'.
Whenever I see it happening again in my own work I do a few different things... Usually some studies of real people (great sites like line-of-action.com come in handy for seeing non-idealized, non celebrities), or another exercise that I find super fun and super helpful!
What happens is, you start with one single face shape, copy/paste it a few times, and then make distinct characters out of each one. It kind of gets me to focus more on the micro details that make people different? After the first few faces, you start having to really reach and get a bit more creative with the ways you can assemble faces. I don't know if I explained that well, but here's a (kinda wonky) example of one time I did the exercise.
Even though those are just heads, the same ideas of playing with shapes kind of work all the way down the body?