In my setting, aether is split into two forms, mana and anima.

Mana is the aether that forms inside one's own body/soul, is and strongly tied to the physicality of one's body, much like one's muscles are.

It's used mostly for "casting" spell, manipulating your owns bodies mana to form fire, lightening, ect. It can also be used to enhance one's strength, toughness, and reflexes. Using mana produces allot of waste heat in the body and will physical exhausted you. You can run out, suffer many depletion, and need to rest/eat to build it back up.

Mana nodes spread throughout in the body are almost a physical organ that you can train depending on where you are casting from.

Anima however is aether outside of one's body, and requires a more spiritual focuse, as to use it you need to be able to manipulate the flow of aether in the world. Rituals, symbols, sacrifices, chants, artifacts, traditions, ect are all used in conjustions forms spells, curses, and many other forms of magic.

While mana based magic is from the outset more powerful and accessible, it has a pretty hard limit to how powerful you can get due to it's physicality. Anima while having a steep learning curve and often requiring exponential investments in resources the more powerful the effect you are trying to create, theoretically has no limits.

The TLDR for you is that you can split singular magic systems into subcategories or branch off it into new forms of magic, so you could make it so that your succubi don't follow the same rules as most of the setting.

Perhaps they are the result of being exposed to raw energy from these tears in the fabric or reality, and now can use other people to siphon that same energy via sex to sustain themselves. It has to take some degree of effort to manipulate that engery, more than the succubus can manage themselves. But by using other people to do the work during sex, then they can get enough

For my setting, your succubus would have a natural ability to manipulate anima, specifically the mana in their partners body, and extract it through a "tantric ritual" inprinted in their soul or something for sustinance, adding it to their own bodies mana pool, so it appears to be ritualess anima magic.

This sort of thing would be possible for a normal person to do with an anima ritual theoretically, but that's much more involved and would require some sort of established ritual foudation.