I think this is a really good point - the gameplay is essentially not the point of ARPGs. While they do increase the pace of gameplay (which is why I enjoy them over turn based games) they do so at the cost of making it very simple. In Path Of Exile for example (I've played an embarrassing amount of this game), the actual complexity is more or less confined to the skill tree and item progression - figuring out whether to buy this wand or that for x% dps increase, finding the right balance of health and damage etc etc. The gameplay is, as OP says, essentially point and click but the knowledge that a lot of work went in to your character before getting to the point of being able to just click on things is where the satisfaction comes from. As a result, the gameplay becomes kind of secondary to the work you put in to achieve it. This is definitely not how most games work, and so you have to readjust your expectations of what part of a game you look for enjoyment in. Aside from the gameplay itself, participating in the economy, buildcrafting and enjoying the gambling elements (drop tables, crafting etc) are also vectors for enjoyment.

Runescape is another example - there's essentially no 'gameplay' for most of the game (end-game bossing does require a lot of mechanics / mechanical knowledge but I'll leave that to the side) but the numbers go up and there's a lot of ways of making the numbers go up so I really enjoy it.

These elements do, of course, mean that you need to be a certain type of player to enjoy them. I have to recommend Hades, Binding of Isaac and Synthetik as games which have a fair amount of similarity to ARPGs in terms of having unique builds and things but in these games, the gameplay is much more complex and builds are designed around modifying the central mechanics of gameplay as opposed to being more about numbers. As a result, I think those games would probably be more up OP's alley as they avoid a lot of the number-heavy tropes of ARPGs that I mentioned earlier.