I just launched TP4, went immediately to Renderers>Advanced and made some changes, then saved the file as "Test". I quit TP4 (but did not Save & Quit this time), relaunched and opened the Test file. The changes to the settings stuck.
If I launch TP4 and check the settings under the default scene, the settings are at their unchanged defaults. So the changed render settings seem to stick to the file in which they are saved, and are not global to TP4 itself, which is what I hoped (so I don't have to keep resetting them).