Neuron Count is fairly pointless... its the shape of the brain that is pretty important and cats have a brain alot more like a humans than a dogs is, its why cats are (unfortunately) used alot in brain studies 😞. Also there are no 'smarter' animals really, just different ways of thinking or approaching life, moving your litter tray made your Kitten (and that is the key word here, Kitten) forget the litter tray, wasnt because it wasnt smart, it more than likely took the LOCATION of the tray as the place to poop, not the object of the tray as the place to poop... a cat will tend to have specific locations it classes as a latrine in its territory and it will use those places even if there is no tray there since its not the tray its using as a marker, but the place its being allowed to poop. Some cats use a different system though and will look for the tray to poop in instead of a location.., my own cats one or two will use a tray if they find it and need it while one of ours will ONLY poop under the piano and will actively avoid using a tray that is placed there and poop next to it... animals (as are humans) are quirky things, all individual, each with their sense of self and ways of doing things.
There is a species of spider hunting spider that has a brain the size of a pin head but it can logically experiment and work out and then remember how to entice/avoid/catch 100's of different species of other spiders from scratch and its got virtually no neurons at all comparatively to a dog.
All animals are sentient to some greater degree or another, as a cat owner for 40 years who has owned and cared for over 15 cats from kitten hood to their eventual deaths of old age, and as someone that spends hours and hours with said animals they are as Sentient as we are, they think, they analyze they have internal monologues and form memories and have as many emotions (if more stronger) than we have as well as a rich language. Sure not to our standards or the same way we do, but they DO, do these things... and ive seen this in many many many other animals ive observed over the decades and its made me come to the humbling realization Humans arent special, not by a long shot... just different. All life is Sentient to a degree, and the idea of sapience should really be ditched.
It also seriously makes you rethink how we should treat a certain sub set of domestic animals as well..
I did the Second Dream aged 38... I enjoyed it and enjoy using my waif. I take it you also dont use Frames that arent the same gender as you in real life?