If there's a problem with the house's support structure, it's possible (and probably even recommended, for the long-term good of the house) to fix it, but beware that you can't perform major surgery on a house without a few consequences.
I bought a two-story house in 2015 that was built around 1930, and had some very pronounced humps on the first floor. Inspection in the basement showed that the main beam holding up the first floor wasn't sitting squarely on its support columns, and was slowly "rolling" off of the columns, making everything uneven.
I had a contractor come and straighten things out, which involved building temporary load-bearing walls in the basement to support the floor above, removing the columns, cutting out the main beam, replacing it with a new laminated lumber beam, setting new lally columns in the concrete floor, re-hanging all of the floor joists from the new beam, and then removing the temporary walls. This took a few weeks, and in the process everything was made laser straight and structurally sound.
- What had been slowly settling for years was jacked up straight over the course of a few days. Up above, drywall, paint, and grout all cracked in places. The kitchen had been remodeled by the previous owners just a few years before (and therefore had been "built straight" on top of a very crooked floor, exactly what you're describing in your question), with the result that tiles popped and cracked, a marble counter broke, and cabinets and drawers were put out of alignment. Fixing this was expensive.
- Every pipe, conduit, and cable in the basement that had crossed from one side of the beam to the other had to be cut down before the work was done and put back together afterwards. In my case that meant that the house was without heat (not a problem, as the work was done in summer) and partly without electricity for the duration of the work.
- The first floor of this house had no subfloor. A hardwood floor was nailed directly to the joists. For most of the length of the house, a wall sits above the main beam, but the living room crosses the beam. At that point, the floor was nailed directly to the beam. When the beam came out, so did a one-foot-wide section of the floor! I ended up having a new floor put in across the entire first floor, again, at some expense.
I wasn't warned about any of this, and it didn't occur to me on my own, so if you're pondering something similar, make sure to keep asking questions!