If you can find 2nd hand stuff that you like for cheap then go nuts.
I’ve got a garage full of 2nd hand stuff that I can’t even give away on FB marketplace because nobody likes the look of it.
IKEA has never been poor quality. It serves its purpose in the market and people seem to like the designs.
I’ve found that this is the problem. The good quality stuff is great and yes it will last multiple generations. However the styling will be long out of date before even the end of the first generation. My parents had old extremely well made furniture that they spent a lot of money in when they first got married. 30 years later the styling was out of date, my mom wanted a change, and they practically couldn’t even give the furniture away because nobody wanted the old style. So now my dad has a guest room in the basement using that furniture.