Ds was similar (now 19yo).
Lots of being called in, lots of silly behaviour (he crept in one time through the fire door at the end of playtime and hid until there was a real panic for him, then jumped out. He thought it was funny. I suspect he probably still does)
He saw no point in writing, or anything that interrupted his play, especially crafts and was inclined to lash out if people crowded him.
He persistently held his pen in a fist at the far end because that was his protest at being told he needed to write for about half of year R. I think eventually the school bribed him to change.
He had glue ear (hearing over winter was about 10%) and was diagnosed with ADHD and ASD in his early teens having been fobbed off with "he's a summer baby - he'll catch up" for years.
Firstly, he found year 1 much better. Learning through play was terrible. Firstly with everyone else playing he was easily distracted, he couldn't hear, he rushed it to get back to what he wanted to do and so year 1 sitting at desks with the teacher talking to all while quiet made a huge difference.
It wasn't just the difference in being able to hear instructions, it was also the sensory issues of the noise all around all day.
At senior school he got put in isolation once and totally ruined it as a potential punishment by requesting that he worked like that all the time because it was so much nicer for him.
Secondly, don't be fobbed off with "no, he hasn't got SEN". He may not be, and it doesn't sound like he is, out of the "normal" parameters, but don't be afraid to push if you feel he is still struggling. Get his hearing checked too. Ds' behaviour was definitely worse when he couldn't hear.
And also boys do tend to be later developing the writing skills. I know screen time is not popular now, but what got ds writing was using the Nintendo DSi messages. He would write messages with his sisters and so needed to do the writing to keep up with them.
I won't say his school life was easy, but he did get easier. I remember asking his year 4 (separate infant/juniors) teacher after a very good parents' evening, whether there were any problems and she said he wasn't a problem at all, he was working above expected, and did what he was told and was a pleasure to have in her classroom. I was expecting her to say "but..." which never came!
He did tend to have love or loath teachers. So teachers loved him or loathed him, and tbh any that loathed it was normally mutual which meant he did as little work as he could get away with which meant they loathed him more...
But more loved him than loathed him, even as they admitted he probably could work a little harder...