11 year old low level behaviour

[Medal123]

My near 11 year old son is lovely, funny and wouldn't hurt a soul. But he's got to a point where he is annoying a lot of people, his friends, teachers etc. He's going to secondary school in September and I'm quite worried he'll continue to annoy older kids.
He's got a strong sense of justice, which is great for bigger issues (like bullying) apart from he'll tell on someone else if they haven't done their homework or looked at him funny etc.
His teachers are constantly telling him off for fiddling, not listening, daydreaming. He's been assessed for any other issues that may be causing this but they have all come back as not being the case. He doesn't have ADHD or ASD.
At home I'm always telling him to hurry up, stop dawdling and the same kinds of low level behaviours like at school. It can take him 40 minutes to get dressed sometimes.
There are no other issues at school but even his friends are pulling away from him because he's annoying them.
We set up plans at school and home and they work for a while but he slips back into his previous behaviour and it starts all over again. Fluffy things like reward charts, positive behaviour plans etc at school and home just aren't effective and secondary school will be more on him than primary.
I'm at a lose! Can any recommend rewards/behaviour incentives for helping this kind of behaviour? I don't want to reward him for just behaving as he should, but he obviously needs some kind of motivation.

Thanks for any help!

Whats wrong with fiddling and daydreaming. I do this a lot

You're talking about fiddling, dawdling, taking ages to get dressed but then putting it next to sentences about friends pulling away

How do the 2 things connect?

Is he being nasty/judgey to his friends and is that pulling them away?

Well, when he reaches secondary school he's likely to start seeing consequences for this behaviour. Fiddling and daydreaming will see him called out in class and probably eventually disciplined if he doesn't cut it out, and teachers often give short shrift to petty tale telling, so I imagine a sharp shock is in store, which might help.

Has he been assessed for a processing disorder?

I wouldn't worry about the older students, your son won't really have much to do with them.
Secondary schools are used to children as you describe please don't worry.
I would concentrate on working on being more organised. Can he help you lay his clothes out the night before, breakfast plate ready, school bag and shoes by the door etc
And continue this in September, I would insist everything stays in his school bag all the time (even if he says he doesn't need it) , help him with his homework schedule.
Over the summer remind him that at secondary school we don't tell on people unless a teacher asks us the question or they have upset you personally.
Get him to join as many extra curricular clubs as possible, the great thing about secondary is it's a fresh start and the beginning of loads of new friendships. Also, the pool to choose friends from is much bigger and therefore it's much easier to find like-minded souls.

I wouldn't reward any strategy, and would go with this is just the way it's got to be.

Another tip is to take a photo of his timetable and have a copy on your phone and a copy on his.
Photocopy his timetable, two for his bag, one for his bedroom wall and one for you.

Is he an only child?