Trying to be certain about existence, the meaning of life, eternity, etc, is no different than trying to be certain about safety, cleanliness, love, or any of the other uncertainties we might try to resolve with compulsions.
If somebody wanted to feel certain about their safety before leaving the house each day, they would eventually get to a point where they could never do enough compulsions to feel safe, and then they wouldn’t leave the house. The same can happen with trying to resolve existential uncertainties before moving ahead with life–eventually it just paralyzes you.
The solution isn’t to resolve the uncertainties, it’s to move ahead with them. They can be there as you do the things that will make you happy and healthy.
One of the challenges with existential uncertainties is that we often believe we should know the answers and we should be certain about life and we need to know.
So cutting out the compulsions that fuel these anxieties will help but it’s also likely you’ll need to throw out some unhelpful beliefs and desires that you’re holding.
It’s impossible to be certain about life, so as long as you desire certainty about it, or believe you should be certain about it, these uncertainties will cause you distress.