It is better to state what issue you are running into specifically than ask how to turn a functionality on or off. The handling of relative paths in ArcGIS Pro is more complex than in ArcMap, and there is no single check box to enable/disable. If you share what you are trying to do and what isn't working than community members can offer suggestions on workflow changes as well as software configuration.
And I assume you have already read Re: How can I "store relative pathnames" in ArcGIS Pro? Although you are interested in not using relative paths, that discussion dives into the general topic of relative paths in ArcGIS Pro.
