GFI breaker trips randomly upon turning on a wall switch?

15 amp GCFI breaker trips randomly upon turning on a 2 switch – wall switch?
It is a bathroom circuit with 2 overhead vanity light fixtures, 2 recessed lights with 2 rotary dial dimmer switches & 2 – 4 gang (regular) outlets & 1 single outlet.
The GCFI breaker test trips successfully. The GCFI breaker may trip multiple times but sometimes reversing which of the 2 vanity light switches to turn on first will resolve the trip problem. And sometimes waiting a short period of time will correct the problem?
I have pulled out the wall outlets to check, tighten & replace 2 of the 5 (double) wall outlets. I also pulled the bigger vanity light off to inspect the direct wiring connections.
I also have tried removing all vanity light bulbs, resetting the GCFI breaker & then turning on the 2 wall switches, then reinstalled all of the lightbulbs.
The GCFI breaker tests fine but it is 25 yrs. old. Could the breaker be weak, causing this random problem.
Should I just replace the GCFI breaker? And I do have another GCFI breaker that is in service that I could possibly swap it with & try that?
It is now happening frequently but in the past it has happened like once every 2-3 months?
I would appreciate all help to find a permanent solution to this reoccurring problem.
Thank you!