Maybe being sentient is about saying no all the time: You are a sack of water made out of carbon and it always wants to simply fall but you have keep saying “no, we stand”, “no, we tilt slightly forward” (walk) etc.
At night, when there’s nothing to do and you’ve already lost your battle against gravity (a comfy bed), maybe the helpful naysayer starts generating bullshit?
Do we have surviving scientists and engineers, or books? Then everything is easy-ish: Progress took time because we didn’t know anything, everything was trial and error. Now we know the correct forms of physical laws or their usable approximations so rebuilding is just a matter of time (generations maybe).
If somehow the collective wisdom is lost, back to the stone ages with you.
edit: High school education brings you to the 1920s tech (era of elements and alloys, just before composites) so maybe if we have any surviving adults, you can have glasses?