The creepiness comes from the way DiCaprio almost label the women he gets in relationships with an expiry label. The age difference doesnt bother me, they are all grown ass adults. The serial dumping at around mid 20 is the creepy thing here, to me it says he doesnt really prioritize or value as much that person's personality and actual being but more what their bodies are (and to be clear theres zero problem having physical attraction, its the pattern and priority being displayed here that is)
Another possibility or pattern is that his relationships end at roughly the same point in the relationship? I didn't look up his past and see if there actually was such a pattern but just hypothetically if he always dates 22 year olds and they break up when the woman hits 25 then the relationships are always ending around the three year point.
You're also removing the agency from the woman he's dating, if Leo doesn't (hypothetically for example) want to get married and settle down with kids and at 25 (or whenever) they want to head in that direction then it's a logical break up point for both people in the relationship.
If you're searching for power relationships you can't stop when you've identified one while rejecting all other potential ones, all variables in a model
must be tested independently. If not, you are performing the rites of a religion, not attempting science.