Picking everything is like picking nothing. Skipping from technique to technique means that no single technique is being given a chance to work for you. I suggest you pick one (it doesn’t matter which – really) and stick with it for at least a week. If it isn’t helpful, then try another. Meanwhile, make sure you are doing the other things that induce sleep. Turn off all device use at least an hour before you want to go to sleep. Do not read in bed. You want to teach yourself that bed is only for sex and for sleeping. Develop a routine that tells your mind and body that it’s time for sleep. That could be a warm shower, brush teeth, get into bed, turn off light, count three things that went well today. Good night. That’s just an example. The point is to have a ritual that signals your system that it is bedtime.
As for who to consult: Since OCD is a general problem, a therapist might be your best bet. If the OCD is interfering with other aspects of your life, you might want to talk to a therapist about how to better manage it.
I wish you well.