The trick to having a varied wardrobe with few pieces is to buy pieces you can mix and match. I have three main colors and most of those are solid colored pieces so they have no patterns to clash with one another. Fortunately, I live in Minnesota where you can layer pieces most of the year.
Here are pictures of four pieces, two black and two persimmon, layered in various ways. The pictures themselves are terrible because I took them with my phone and because I didn’t spend a lot of time styling the clothes but they are enough to give you and idea of how I mix them.

That’s seven looks from those four pieces. If I wear them with black slacks one time then persimmon slacks the next time that makes enough variety for two weeks.
Before I add any of the four pieces of sapphire blue.

Or any of the five cardigans, hoodies, or blazers I also own in these colors.

And one more persimmon shirt I didn’t show you plus duplicates of the shawl collared black shirt.
I haven’t done the math to see how many outfits I can actually assemble from these fifteen pieces but I’m pretty sure I could wear something different every day for a month or more.
Before I add scarves.
TTYL,
Linda