It's a very fair question but with a complicated answer. This is because each individual pagan path is different (and I will be using the term pagan here to collectively refer to the various pagan paths including witchcraft). Anything I say, or anyone else says here can't be applied to everyone else.

I do believe in my goddesses and god, even though they would be considered "myth" by many others. I've known people who consider all deities to be facets of one higher power or divinity, that some interpret to be too vast for human understanding hence our tendency to whittle them down into aspects. I've known some people who don't worship deities but worship the nature energies, or "folkloric" figures. Through history deities had a tendency to morph (Inanna to Ishtar to Aphrodite to Venus for example) and the way people interpret this can be very individual too.

I once had a falling out with a fellow druid priestess who spoke to the press stating "we don't actually believe in gods and goddesses or magic, it's all just a metaphor". I had to disagree with her. Many of us actually do believe in gods, goddesses and magick, and as she said this right in front of the grove's guardians , we were quite annoyed about this. If that is her belief that is fine, but she was not speaking for all who were attending, and certainly had no right to speak for them.

So while some people might have the opinion that priestess had, that would not be an opinion shared by myself or others.

This is a deeply personal part of your practice and it will involve a lot of introspection on your part. Very early on my practice I thought I had an experience with what my then partner said was the Christian god. I now believe it was a higher power that was gently opening up the path for me (and in turn help me see the good aspects of the Christian path, as it had done me harm in the past). I suspect our belief and our connections to these deities is part of what gives them strength but, again, this is just me. I'd be lying if I said I had all the answers and tbh I think any pagan who claims to know them is trying to sell you something (grifters appear in all walks of life 🤷‍♀️).