CRNAs don’t exist in the UK (as this is a UK based forum I’m presuming you are here). The closest thing is the anaesthesia associate (AA), which is a medical associate profession (MAP). There’s currently a lot of debate over the need for, use of and scope of MAPs.
If you want to give anaesthetics to people then the best route for this is to study medicine, get a post grad training post in anaesthesia and become an anaesthetist.
There are nursing roles which are much more focussed on “sciencey” stuff, for example critical care nursing. It may be worth exploring these to see if they interest you.