I don't think we're supposed to miss getting high, but it's a truth, when I think about it, I do miss it. So I try not to think about it.
Where you found yourself in habitual daily use of pot mirrors my experience.
For 20 years that is what I looked forward to every day, that escape at the end of the day. Of course it wasn't limited to the end of the day, but without fail, it was an everyday occurrence. The isolation and unhappiness grew. Eventually leading to divorce and a financial restart after 15 years of marriage. Important, though difficult, changes there.
You hit on a most important point with, "And whatever issues I had as that made me want to be high all the time way back when I started, these haven't gone away." This is what we need to address, it seems. Those reasons why the escape we found in drugs was/ is so compelling. What are we trying to escape, or hide from. Probably something inside ourselves.
Whether or not working the NA program will provide the answers is a good question. I know of the steps but haven't worked a single one, at least not with a sponsor, hence I've gotten nowhere with them. Certainly it could help provide insight, maybe offer direction.
I tried a therapist, twice in fact. That was such a waste of time I laugh now thinking of it. The suggestion to "get out in nature, make time for yourself, let the natural world inspire you" was one therapists advice. Ha, he didn't have a CLUE what he was talking about. He had no idea that's precisely what I did when tripping!
I don't much talk about my doc because they're generally not considered addictive, not in the way other drugs are. People pick them up and put them down, routinely. They're not obsessed by them. Which is why it's so hard to find anyone to relate to when talking about this. It's a difficult addiction/ obsession to explain in any rational way.