He sounds like my DC with ADHD. I kept just pushing on with DS1 hoping it would get better, and I think it did damage our relationship because I found it very difficult to cope with him. I wish I had understood him better when he was younger.
DS2 has just turned 8 and has been on medication since the start of the year. A lot of the behaviours are still there - he will absolutely evangelise at you about the glory of our Lord Jesus various models of train or explain a youtube video in excruciating detail, for example, BUT he is actually able to take on board if we ask him to hold on for a second because we need to deal with something else, and if I say actually DS do you know what, I just don't have the energy to listen to trains right now, he will go away and find something else to do, which I would have been astonished if DS1 did once, ever. And he's just 80% less draining so I can actually enjoy his company even though he can still be hard work. It's balanced now and worth it because the things I can do to manage his difficulties actually work, rather than everything being difficult all the time, if that makes sense?
I know you have said you don't think there is anything to look at developmentally but I think people often misunderstand what ADHD actually is, I definitely did. These are the official criteria paraphrased, obviously an actual assessment is much more in depth, but you only need 6 from either list and I've bolded the five which have been mentioned in this thread alone.
Hyperactivity/Impulsivity -
Fidgets constantly/more than other children
Doesn't sit still, when other children his age can (e.g. at the table)
Runs about constantly and/or climbs everything
Seems "on the go" all the time/acts like they have an everlasting battery (ie, doesn't get "tired out" no matter how much exercise they get)
Doesn't do anything quietly
Talks excessively
Blurts out answers before a question is finished/can't wait for turn in conversation
Difficulty with taking turns in general
Interrupts or intrudes on people (e.g. butts in, doesn't respect personal space)
Inattention - (IME harder to spot in younger children)
Makes careless mistakes, tends to rush things
Trouble sustaining attention on non-preferred activities
Doesn't seem to listen when you speak to him directly
Does not complete tasks/follow instructions because they get sidetracked
Difficulty organising self or getting things in the correct sequence
Getting them to do anything boring is like pulling teeth
Loses everything
Easily distracted by thoughts or unrelated stimulus
Forgetful
The fact you've said these behaviours are affecting him socially, in that his peers are put off by them, as well as the fact you're worrying that they are affecting your relationship to me makes it the right time to query this with a professional.