Oil comes in the combustion chamber 3 places. Rings, Valves, and through vacuum path.
If it is the vacuum path some things might be culprit like a PCV valve stuck open, or excess blowby.
If it comes through the valves you need new seats. Easy to replace just time consuming.
If it comes through the rings then that sucks for you. Rebuild the bottom end or look for a motor swap.
Something that works for a band-aid solution is to use a thicker weight oil. Or you can add the oil additives that thicken your oil. I dont recommend additives.
What you need to do is perform a leakdown test. This will tell you where you are loosing compression by oil seeping in.