FWIW our curriculum is much more in line with what ultramarina posted. Our provincial kindergarten program was re-written recently to be more play based. I don't think they ever hold kids back (not that there aren't problems with that, some kids might benefit but that's a whole other topic).
My 2e DS was behind in JK/SK (we have two years of kindergarten here). Grade 1 he was slightly behind in reading and really behind in writing. We tested and his scores were all over the place (they suspect a processing speed LD but will test again when he's older to confirm). We got an IEP for the last half of grade 1 that allowed scribing and advocated for a better teacher match for this year. This year he's made huge improvements and his reading and writing are at grade level and they hardly ever use the accommodations in the IEP (they are still there in case the increased writing as he gets older becomes an issue again).
More importantly school is less of a battle and I attribute that to a better teacher match. The worst part of last year was that DS started thinking he was "stupid" because he was struggling with writing while other kids weren't. He was extremely frustrated and it came out in his behavior. The teacher's attitude towards him probably didn't help things. After testing we had a big talk about how some things were really easy for him (math & science) and that some things were going to be more of a challenge but that didn't mean he wasn't smart. It has also helped him understand his classmates that struggle in things that he is good at. His new teacher believes in him and DS knows it and does much better at showing his abilities at school while working through his challenges.
In our world gifted doesn't mean accelerated or high achieving in everything. In some areas he blows our minds (and the teachers) and then in others he struggles. Asynchronous is his middle name.
Thank you for sharing your experiences. I'm wondering how much everything is just up to chance with teacher placement. Some teachers are great, some not so much, some do well with some children and others click with different types. It wasn't until I started reading about giftedness that asynchronous (and other terms) became part of my vocabulary and now DS is starting to fit into an explanation.
