I'm a fairly strong believer in the idea that the only way to develop human like intelligence, is in adaptation to a situation in which human-like intelligence is advantageous.
Which, in the ordinary course of things, would be a situation that your basic pastry toaster does not face.
So it seems unlikely that a toaster would be the site of an independently-developed synthetic intelligence enough like ourselves for us to see it as a person.
That said, a toaster might very well be the chosen home or embodiment of a pre-existing human-ish synthetic intelligence. Which of course leads me to wonder what kind of relationship the intelligence has with breadstuffs, breakfasts, and snack heating.
Obviously Lister's "talky toaster" is one take. That's what you might call "leaning in" to the job, and finding the truth in the maxim that any calling can be great when greatly pursued. It would seem just as likely that someone else might resent their current embodiment as a toaster and flatly refuse to have anything to do with it. Or treat it as a minor aspect of their life while they work on some philosophical magnum opus, the way Einstein supported himself as a patent inspector while working on the theory of Relativity.
But, honestly? Roko's bread fetish, IMO, makes her an ideal candidate for embodiment as a toaster. It takes just a few things though, that might be difficult. First, she'd have to be okay with her kink. And I mean, really okay. The sort of quiet, straightforward acknowlegement that can be partaken of without shame and without the kind of desperate, defiant, hyperbole that marks a lot of people desperately trying too hard to be okay with something about themselves. Second, she'd need a partner who appreciates bread, and toasted goods, and who could treat her with basic sophont dignity and honest respect, and value her work as an expression of herself and value the trust she's placing in them in allowing him (or her or them) to be so close as to fully understand it. If her partner was merely consuming its result, or being titillated or disgusted or embarrassed by her emotional involvement with it, honestly she might as well be in a solo scene, and there's not much emotional fulfillment in that.
That's probably a biological partner, because part of what makes it meaningful, aside from the sensual experience of breads, is the idea of physically eating it and deriving sustenance from it - still a bit difficult for synthetics in the QCverse as far as I know.
And honestly, it's finding this partner capable of understanding, treating her with dignity, and capable of appreciating her involvement - someone who would feel privileged that they should be so trusted by her as to be allowed to witness it - that would be the most difficult part of setting up this little idyll.
But, that was always the case, for anyone who has a minority sexual modality. It's always finding the right partner/s that's the hard part.