How to flavor plain yogurt?

Starting to eat more yogurt and like the berry flavors, but kinda hate all the little single serving tubs. I’d like to buy the bigger tubs to reduce waste and save some money but all I can really find is plain and vanilla.
Tried googling and got a lot of hits for just mixing stuff in, but that’s not really what I’m after. I hate the yogurt with big hunks of fruit. I’m thinking maybe just throw some plain yogurt and fruit in a blender and mix it up that way. I like the icelandic stuff the best but find it a little thick and have been adding a little milk to thin it out. Figured I’d throw that in too.
However, I’m worried I’ll end up with some whipped concoction that isn’t yogurt and isn’t quite a smoothie. Not really sure what happens to yogurt when you blend it. Would a food processor work better?
What do ya’ll do? How do you make that good, smooth berry yogurt when starting with plain yogurt?

How to flavor plain yogurt?