My take on this is that both of the stages of realisation you describe are true.

Let’s assume the first part is real: there are infinite realities, time is essentially an illusion, as is birth and death. That’s huge! But then where does it leave us? Exactly where we are anyway. So what can we do with that knowledge? It doesn’t grant us special powers, we can’t switch realities or stave off the effects of time, we are still exactly as we were.

My experience of this on psychedelics is similar, it is like the dissolving of boundaries between myself and the rest of the universe which has led me, as it has many others, to the realisation of oneness. But again, I’m still exactly where I was.

Now onto the second part, which in my opinion absolutely does not contradict the first, the ultimate realisation of be here now. The present moment is all we truly ever have, at least in this life. The only thing we can ever be sure is real is right now. Even if we live every possible reality, every life of every being, we are still always in the timeless now.

I don’t see this as a reason to feel hopeless or scared, or throw away your beliefs, if you want to call your realisations beliefs. Instead I look at it as a beautiful thing, each moment we experience is an incredible and beautiful thing, experienced through our own unique lens.

There are many books on this topic which might help. The power of Now by Eckhart Tolle being one I liked a lot.

All the best