Nothing wrong with IKEA, they do some brilliant things. It's buying from nowhere but IKEA where the issue is but that's true for all shops. I like their fabrics (like a PP I bought cheap as chips fabric there then had pinch pleat, full length curtains made up with interlining for a bay window and they look great), their kitchenware is good as well, and their rugs. I have something from IKEA in every room of our house but don't go for the famous top of range stuff because it is ubiquitous.
You get more for your money shopping second hand. Ebay, gumtree, FBMP are all good for this plus charity shops and auction houses. Or beg, borrow or steal hand-me-downs from family and friends. Whenever I need something for the house I always look for it second hand first. As the great Patsy Stone said 'One should never be the oldest thing in ones house'. It doesn't need to be a valuable antique, as long as you love it.
You can do a lot with paint. Think about colour drenching, or colour blocking or painting the ceiling and woodwork any colour but white. Personally I prefer a whole small room wallpapered to a feature wall in a bigger room but do what you like.
Art work should be meaningful to you, not something generic from IKEA. I have framed artwork by family members (including my kids), photos I've taken, meaningful postcards, studio glass and pottery bought second hand, a massive poster DH took home from a scientific conference, lots of things from the places DH and I grew up or things we've bought on holiday. Plus plants in nice pots (another thing IKEA is good at and supermarket house plants are pretty good as well, you don't need to spend a fortune at the likes of Patch Plants). But think about how it's all positioned, have a gallery wall for small pictures or maybe have a special one next to your bed or a quiet reading chair so you can look at it each day or have a single large picture somewhere it becomes a main feature. Don't scatter pictures about willy nilly, half the battle is in the styling.
I think it's fine to get high street or high end stuff as well as part of the mix, particularly as you get older and can afford more. But, e.g. my expensive new bookshelves are grounded by my reupholstered inherited chaise longue and the battered old trunk we use as a coffee table that DH bought as a student 30 years ago.
And finally, declutter and have enough storage for what you need and love. And take your time finding things you love and always donate or sell on things if you don't need them anymore. So much cheap furniture ends up in landfill, if you buy and sell second hand you are preventing that happening.