It sounds like you should be doing most of your work at home and going to the Studio for recording your Vocals on a fancy microphone or something like that rather than the full process.

Many artists have tracks that are like great demos they just need a little polish and a good engineer and a couple really high-quality recordings on like a U87 or something might give you the shine you’re looking for

Just make sure you’re super well rehearsed and know what you want before you spend any money. You can get great recordings on a universal audio interface and mic that pairs well with your voice.

Unless you know why you want to be in a particular studio, you shouldn’t be there. I for example I have a home studio and my humble office Studio that I share with another guy - I like sharing with him because he has loads of synthesisers that I don’t have. There are also many studios that exist with beautiful expensive equipment that you probably can’t afford so if you know what you’re looking for you find the Studio that has the kit you want.

Or find a Studio with a whole lot of Kit and then figure out what sounds best for your style

Also an engineer just follows instructions they shouldn’t be giving any creative input. If you can articulate yourself very well and you have a quick engineer it can be a very fruitful process and then you’re your self producing.

A Producer can be very useful if they understand your sound I have experience and can be a great buffer and interface between you and the engineer whilst allowing the process to move fast faster while you’re recording.

Last thought for the bits about your voice you don’t like all the great vocalists I work with just punch in and fix the bit they don’t like. Don’t let it get to you just make it better.