To an extent I can have this problem, I can draw different features but there's a small number of "go to" face and body types that I default to, the best remedy for anyone is always just to reference real people.
Here's a pretty awesome blog to help with that! You can set it to randomize, which is great for practicing different facial structures.
On a reading end, I'm not a fan but I pretty much expect 90% of visual work to have SFS, and about the same percentage of people use the "it's my style" excuse to not get out of their comfort zone; so I just turn my brain off or go somewhere else. It always bothers me that most people don't understand what a 'style' is, and that no style can keep you from having variety in your work, it's just you as an artist being lazy (which is fine, people can do whatever they want, I just hate when people use excuses) Admittedly it doesn't bother me when the artist has a style that can pull it off, and still make the characters distinguishable enough to tell them apart, but when it's just SO BAD that everyone looks like the same character with different clothes; I just can't.
Your art is distinguishable enough to tell everyone apart, OP, so don't worry about it. Sorry if this came off rude, I'm kind of passionate about the subject.