Like so many things druids have as many experiences and beliefs as there are stars in the sky. It's the way we are and you don't have to believe what any one or group says is the truth, but they do deserve recognition that it is their experience and they're entitled to have it, to share it and to be respected rather than ridiculed. And it still doesn't have to be true for you, right now or indeed ever.
In the past 40+ years I have believed in a single deity, a pantheon of deities, deities as myth or multiple expressions of a creative force, deity as a psychological expression, no deity at all, and considered other things in between, they've all been my truth at the time and I've learned from and through those experiences I've chosen or had. I wouldn't thank anyone, be they Christian fundamentalist or sceptical atheist druid, for telling me I was simply wrong or deluded, I think I and you and anyone incarnated, is worth better than that.
My own explorations of spirituality have led me among other things into trying, open minded, possession ritual within the Voudoun and Salish traditions, which are intended as a direct invitation to possess and take over for a short period, for the purpose of healing, not for some ungodly selfish deity to embarrass, humiliate or damage the person or group. The Salish ritual I was too resistant to go with the urge that arose, my ego held it back, but nonetheless it was a unique experience and not a threatening one in any way.
The Voudoun ritual I have done more often, and every time it "worked", and yet most times it wasn't a full possession because in all but one case I retained some awareness, an observer that was able to recall at least parts of what I did. I was told that wasn't "proper" but it was my mind refusing to let go control, and yet it was partial, the invitation, the receiving, the experience that far, but it had to be what it was for me, an experience incomplete in the sense of those that practice complete possession and surrender. For me it was enough. The times I "lost" myself almost completely in the process brought me what I needed, not what the tradition said I should have, but it is not my tradition so I wouldn't expect to be the same as anyone for whom it is.
Interestingly the most lost I got was the last time I did the ritual, about 18 months ago and I had very little recall of anything bar a partial physical memory that "felt" like I had been scuttling sideways like a crab but then nothing much. The group (it is always a group ritual) humiliated me unintentionally afterward and the next morning by delighting in telling me what I'd "done" as if I had been some drunk student dancing on tables that had come on to all the guys. They were laughing but I couldn't laugh with them, so I moved away from it as the experience itself had been healing, but the reactions were not. I still got exactly what I needed, strangely. It turned out what they saw was me possessed by a power or spirit animal that actually is my most powerful protector in the shamanic tradition, and it was scary for them to see me really let go in that power so they mocked it to make themselves feel safe. I got verification of the ritual, of the impact in terms of healing on some of those present, and knew who was scared and what I needed to do for my own healing, which was move on. It was a clear direction which pushed me into both a period of deep self reflection and also deeper by far into my druidic practice, letting all the shamanic teaching and practice go for a period that has as yet not ended. Without that experience of complete surrender and what followed, I would probably be still living that life, doing those things, and not where and who I am.
So if it doesn't suit you or it scares you, don't go there, let those that do have their experience, good or bad it is what they need, not necessarily what they want, but the possession rituals are about surrender rather than control so folk should be careful what they ask for and then perhaps look at what they got and work out why it was a healing, even if it felt like the lancing of a painful abscess it will almost certainly have had a healing intention and purpose.
I may never undertake that ritual again, but if I do it would be with greater faith and trust in myself and the power that I surrender to, and with greater care over who I experience it with but knowing some just aren't ready, some go to make a big ego show of "letting go" which is more showing off disinhibited behaviour for general appreciation and admiration than genuine possession by a healing force, be it Lua or deity of another tradition or power animal or disincarnated soul.
Just go your own path and let live. There are no two identical paths in the forest, I find, what is true for me is not what anyone else tells me is right or wrong, just what I choose to engage with and how I experience and then interpret that experience. Deity or my own psyche, it works for me best if I don't try and define for so long that I lose the heart of it all in exercising the brain