I can only comment on my experience op
It became very quickly apparent once my Ds started reception that he was finding it very difficult to cope with demands of mainstream school life. Prior to this he had spent 18 months in the schools pre school with no concerns. I desperately wanted him to stay in this mainstream school as it's a wonderful village school. The school head was fantastic. Provided 1:1 support. Paid for behavioural support workers. Ed psy report. Referred to Cyps. Adapted timetable for Ds. Let him have a reduced timetable (sometimes only 2 hours a day and even that was sometimes unmanageable for him). We begged for extra funding from county, eventually got emergency funding (after threatening legal action) we got the highest tier while we went through the EHCP process. School paid for Ds to attend a private sen nursery while EHCP was processed. School even paid for autism trained staff to come into school to try and help him integrate/cope. I couldn't have asked for more from the headteacher.
During this time my Ds was very disregulated. Any friendships made in pre school we're now hanging by a thread and he chose to play alone. He was self harming and became very unpredictable and a danger to others in school, throwing items when he became disregulated etc. It very very quickly snowballed. And I mean over a few months. He was excluded twice and the head warned that he was at risk of permanent exclusion.
Long story short is that the school said they could no longer cope with his needs. Funds ran out and all local mainstream schools said they wouldn't be able to manage him either. My only choice was going to be home ed or a specialist school. Nearest specialist school is 20 miles away.
I was apprehensive and actually felt I'd really let my Ds down as I knew he would have to attend a special school. Let me tell you....
The difference in him is astronomical. He's like the little happy, carefree boy he was in pre school. He enjoys school. He smiles in school now. He has friends. He feels safe. He knows the boundaries. He can see other dc who are similar to him and can now see that he is not alone, he is not naughty, he is not a bad boy like he said he was. He is thriving and he is also learning now. He wasn't learning in mainstream. In mainstream it was very much about controlling his behaviour.
Because the staff in a special school are trained to deal with a huge range of dc with perplex needs they are just fantastic. My Ds doesn't always receive 1:1 now because now he doesn't need it. The staff don't need to give him that in the environment he is in. There is still usually 3-4 staff per 5 dc so if my Ds needs additional support for something, it is available
Don't write off other schools like I did. My hand was forced and I'm glad it was. It was without doubt the best thing for my Ds.
FWIW he's been diagnosed with autism and adhd. There was a time he couldn't handle 2 hours in mainstream with 2:1 support. He now does full days (pre covid) and he doesn't self harm anymore, he's happy and he's learning. I wish you the very best op, go and look at other schools, find out what you need to. You may even be able to get hold of a parent Governor from one of the special schools and speak to them directly?
Sorry for the epic post... good luck op