I think one thing people don't understand when it comes to SzPD (and avolition more broadly) is that just because someone is doing something doesn't mean they actually want to do that thing.
I've tried to explain to therapists and such that at any given time, I don't want to do anything. I don't have any long term goals, and I don't have the drive to do any of the things normal people tend to centre their lives around (i.e. having a successful career, travelling, starting a family). If I had it my way I would never do anything at all. I wouldn't even exist.
And yet every single time the response I get is "But you're working this job! You're studying this thing! You're doing this hobby!" as if that's some kind of undeniable proof that I actually do have desires and goals. But the real reason is I simply don't have a choice. You can't just not work in the world we live in.
If I were to just not get a job, I would have to deal with not having food or utilities or home, which would force me into more things I don't want to do. And so if I have to have a job, I'll pick whatever I'm best at and is the least mind-numbing. That's not because I'm actually super passionate about that thing, I'm just picking the option that I don't want to do the least.
I don't really feel that strongly about hobbies and such, but unfortunately I am a human being who can't survive off of literally zero stimulation 24/7. I just pick the things that sustain my attention the most, it doesn't mean that I'm passionate about them. Again, I'm just going with whatever I don't want to do the least. And even then I spend most of my free time not engaging with said "hobbies".
By that point they normally just default to "Well, you haven't killed yourself yet, so that must mean something!" but it really, really doesn't. Killing myself is way more effort and discomfort for something that isn't even guaranteed to work.
The only way you could literally do nothing is if you just sat in a room and starved to death, which would be incredibly painful and incredibly boring. It's much easier to just passively go along with the flow, which involves doing things and participating in society. That doesn't mean I actually want to do it. It just means it's the option that takes the least effort.