I suspect this is part of the issue we had for my son.
We started potty training at 18 months when he started removing his own nappies. We just weren't cracking it.
He is autistic and speech delayed so I reached out for help from the HV team who scolded me for not waiting for signs of readiness.
We waited until 2, then tried again when he was starting to pull his own pants up, again we just couldn't crack it. We tried to go to routine rather than waiting for communication to develop, and he was completely disinterested in rewards or rather, he didn't associate the reward with the behaviour.
Then at 3 we were desperate. We'd had the last 2 weeks of the school holidays with semi-success, but then nursery insisted on a nappies for nursery, pants for home policy as he was still frequently having accidents as they were relying on him verbally communicating (which just wasn't happening as he was non-verbal), he regressed, had anxiety around potties and toilets and then started withholding his bowel movements.
By almost 4 the HV got back in touch and I said he just isn't showing enough signs of readiness, and I got scolded again for waiting for signs of readiness because that's just not how it's done now, we don't wait for signs of readiness, we create routine and structure.
She sent me on an ERIC webinar specifically for SEN kids.
I got told don't wait for signs of readiness, but don't start unless they're ready. Always change nappies in the bathroom to create an association, unless your child has bathroom anxiety. Never ever use nappies or pull ups, unless your child withholds bowel movements and then you always use nappies or pull ups. Always praise them for doing a good job, but never praise them because sometimes it draws attention to what they're doing and makes them panic.
My head was spinning by the end of it.
I even remember at 7-8 months old I asked about elimination communication, and was laughed at for being a "crunchy mum". But I wish I'd bloody done it.
DS is almost 7 and they still won't refer to the continence team.