I would choose a dark porcelain tile like the wall color but IMO if you do that the wall should actually match the tile so you might have to paint one more time and then a white high glass vanity some good lighting and a great piece of art above the toilet

A dark floor will work the best with what you have. If you don't want a dark space, as you state above, the colour scheme is completely wrong for "not dark". That doesn't mean it won't be beautiful. It will be. I will be gorgeous...and dark. You don't want "gloomy". I think that is a better wording for it.

A room without a window + dark paint = dark. OK. So long as you accept that concept and rid yourself of the 'don't want dark' concept, you'll be fine. Dark can be dramatic....but it can also be gloomy which is what you don't want.

Use the drama to create a spectacular space. You are half way there to spectacular. Dark and spectacular. Go with it. It will work so long as you stick with the program (the program being Dark = Spectacular).

If you want "not too dark" you have to get rid of the dark paint. You love the paint and you love the look so just work with the paint and the look that you have created: Dark = Spectacular.

A deep coloured floor (something other than wood-look is really needed here). Your space is unique so try to stay away from "everybody is using this product". Unique becomes normal if you work with something "everyone is using".

I would keep searching for a magnificent, unique, dark floor that screams out "Spectacular". And go with your gut. You've got a great eye. Trust it.

Thanks for the great comments.
Cancork floor, you are right, I just need to go with it! Got to be brave! I am definitely going with a dark floor and dark unit for the sink. These are the floor tiles that I like. I'm going to go with it like you say, I can't just stop halfway as it won't look right.