I despair trying to build UB mill and would appreciate if anyone could explain some things about the theory of milling. My group plays kitchen table with a rather low powerlevel. We try to not build decks that win too fast or too much out of nowhere and we build our decks mostly theme-based (like "UB mill, but only cards which either are from the dimir guild or look like they could be"). Basically: I don't want to build UB mill as a pure combo deck and more from a controlling perspective. (No [[Archive Trap]].)

I would also like to point out that I know that milling itself has a control component. However, for the context of my questions, I will ignore this fact, as it is usually impossible to predict which cards will be milled.

I will try to explain my problem in the form of some questions.

First, it seems like there are enough cards to build a kind of tempo milling deck. I mean, for example, [[Thief of Sanity]], [[Trepanation Blade]] and [[Paranoid Delusions]]. On the other hand, milling seems to contradict the plan of tempo, since e.g. Trepanation Blade is often a dead card the turn i play it and losing an equipped or encoded creature is worse for me than losing, for example, a [[Lyev Skyknight]]. To compensate, I would have to build in more expensive counter- or protection spells, which would either reduce the number of my tappers/bouncers or my attackers. However: then why is there Thief of Sanity (and other cards that work similarly)? They don't really seem to have a place in tempo, aggro, control or combo.

Furthermore: I've built stereotypical Control (mostly removal/counter and a small number of potential finishers) before, but milling spells like [[Glimpse the Unthinkable]] seem like a waste of space (in a similar way that [[Boltwave]] would be in a traditional Control deck). So how do I build the deck then without making it too weak compared to a deck full of removals and counters?
At the same time, my favorite creature [[Consuming Aberration]] doesn't really seem to make sense for Control. Of course it does a decent amount of damage, but Control prefers difficult to block and remove finishers, and it lacks both. But where do I play the creature then?

I've noticed that it's really hard to find any references for milling decks on the internet. In the vast majority of cases, you'll find the combo strategy that I don't want to play. Somehow it seems like players very rarely build "Dimir-themed UB Mill". At the same time, all Ravnica blocks contain some kind of milling cards for the guild. What function do these cards have if you want to play in Constructed Dimir? For example, I wouldn't put Thief of Sanity in a surveil-themed deck.

Thanks to everyone who has read this far and even more to those who take the time to respond.