I have read that you can mix polish with gel, I've tried it and it works great. But has anyone tried to mix polish into Brisa glosser?

I assume you are talking about the Finishing Gloss gel? No I haven't ... I use the Brisa coloured gels for polishing ... they mix and glide on so smoothly on their own.

IMO the top coat would be too thin and dilute the colour too much. I haven't tried it but TBH I am not tempted