It might be just me, but I can't really say the tone of Ben/Bess' dom setting is similar to Sera's - whilst Sera is stern yet understanding of the sub's mental gears and uses them to fulfill her wants and needs, Ben/Bess is closer to a stereotypical "do this because I said so, you [demeaning term]" dom. Not that it's a bad thing, mind you - if you're looking for D/s experiences, this means TiTS may cover several of its flavours.
That's most likely on me for not communicating my thoughts clearly, but I didn't mean that Bess' content is similar in tone to Sera's, quite the opposite in fact. I told OP that there are no characters quite like her, and any alternatives listed are different in one or several major ways.
Because you are right in that on top of being much more forceful and severe in her demands and punishments, Sera's D/s also goes much deeper into the mental inner workings of that dynamic. She also lives a life of her kink and demands from PC to dive pretty deep into it whenever they are around her. It can really pull a normalfag like myself out of experience, make them scratch their head and roll their eyes. I love Sera, but mostly
not for the crazy sex.
On the other hand, Bess provides the same level of kink immersion that an average couple can try on and off during a couple of weekends without any issues. It's all harmless and inconsequential fun, which can be great sometimes. Looking at NS' and Jim's styles side by side in Inessa can make the differences really stand out.
I'd even download So on a Siegwulfe shell if needs be.
But the doge robot lady is nice too. And I'm sure that So's implementation doesn't hinge on finding a body. Hell, IIRC the body is completely optional for all of her routes.