By overbite, do you mean overjet or deep bite?
I am 38 and have a deep bite and a class 2 bite, and started orthodontic treatment back in June. I have a thread about it here where I have been posting updates, but I'll go over what will be done for me for each of these aspects of my bite. I was basically told by my ortho and another I got a consult from that invisalign/aligners wouldn't be great for my case.
My class 2 bite would give me an overjet, except that my upper incisors are tilted inward (so a class 2 division 2 bite). I am about to start getting that corrected with a Carriere appliance. Basically a different way of using elastics (specifically class 2 elastics, from upper canines to lower first molars, for me). I was told I'll have the Carriere for 4-6 months. 4mm sounds larger than what I would have, though, but I'm not sure. Some orthodontists might suggest extracting premolars for an overjet of that size, and/or they may suggest some other sort of distalizer other than a Carriere.
For my deep bite, braces by themselves can correct it, but that can be slow. My deep bite was I think 75-85%, meaning my upper incisors covered somewhere between 75 and 85% of my lower incisors when I bite down. Once I have full braces, I will be getting posterior box elastics to help bring the rear teeth together, which will then cause the deep bite to open up some in the front. I am also probably going to get bite turbos on the back of my upper incisors, which will prevent me from biting down on the lower front brackets, and will also help with the bite opening up quicker.
I'd definitely say go get a few free consultations (assuming orthodontists in your area do them for free), and you'll get to hear what specifically would be recommended for a treatment for you. If you go to, say, three and don't like what they're suggesting, go to some more. If you're not happy with what any orthodontist suggests, then maybe you don't do anything? But I think, if you do want to correct your bite, you will find an ortho somewhere that proposes a treatment you'd be happy with.