How to avoid N+1 problem when loading more results in blade?

You can add additional levels of eager loading with the dot notation:

with(['children.children.children'])

This would load 3 levels of comments :)

Wait... it reduced the number of queries by a little bit. Might actually be onto something.

I think I need to somehow load the children's children AND its relationships, and then do that for every single child.

You don't need the repetition - in fact you're possibly overwriting the previous values.

Try:

$comments = Comment::with([
                    'children.children.children.children.children',
                    'owner',
                    'savedComments',
                    'votes'
                ])
                ->where('submission_id', $submission->id)
                ->whereNull('parent_id')
                ->orderBy('removed','asc')
                ->orderBy($sortBy, $direction)
                ->paginate(200);

This reduces my number of queries drastically, but I still have a N+1 problem here.

I use this package: https://github.com/beyondcode/laravel-query-detector to let me know.

I also log all into my log file.

This is what it looks like now: https://pastebin.com/Fvemy0xT

So down from 156 queries to 55.

Yeah, you would need the other relationships too.

What you could try is add the with() to the relationship:

function children() {
    return $this->hasMany(...)->with(['savedComments', ...]);
}

That might reduce it further but I'm not sure. Don't think I have tried that before :)

I've tried this too. Doesn't solve my issue, sadly.

I think what I'll have to do is load only the parent comments. For every child comment, I'll load them through an API call.

Take a look at this package. You can use it for the nested comments.

https://github.com/lazychaser/laravel-nestedset

This returns ErrorException (E_NOTICE) Undefined offset: 0