If a girl takes you out to eat and pays...is that like giving you confirmation to screw?
Not confirmation, but I'd say the odds are in your favor.
She casually took me out multiple times, for sandwiches, you know, nothing fancy.
Now I'm thinking I should have at least made out with her lol
Why haven't you?
I gotta say, this sounds like you're very shy, passive and insecure. You're looking for confirmation/permission to escalate, you won't take even a slight risk and you seek certainty.
Let me tell you, there is never certainty with these things unless she makes the first move which is generally unlikely. You need to man up and make a move, someone has to go first and usually it's expected the man to do so. Be a man and take the hint.
If she has to force it by going first you'll become less appealing to her. Reading the hints and taking the risk is sexy, best way to show that you are socially competent and have the balls.
Continuing to be passive about this will either land you firmly in the friendzone or she'll lose interest completely and ghost you.