My 3-year-old autistic son is very self-absorbed and therapy doesn’t seem to be helping — looking for hope or advice

My 3-year-old son has ASD. He has very poor receptive language and no words yet. He’s also extremely self-directed — spends most of his time in his own world, and doesn’t seem to respond much to us no matter what we try.

We’ve been doing therapy for a while (mostly play-based and speech), but it doesn’t seem to be making a visible difference. He still rarely engages with us or follows simple instructions. He doesn't even notice when we talk to him or give instructions.

Has anyone here had a child who was like this at 3 or 4 — very much in their own world with minimal understanding or response — who eventually showed progress? What helped? What kind of therapy or approach made the biggest difference for your child? Even small anecdotes of hope would mean a lot right now. I am losing hope .

Thank you in advance to anyone who shares. ❤️