Welcome, Lyn and pretty blue quaker!
Yes, laddering IS boring
but it's also a form of flooding, as Wolf mentioned. At 5 months of age, you have a VERY young child there so I hope that you are providing some nice soft food for it and not free-feeding seeds or pellets. Quakers are excellent eaters so you should have no problem getting it to eat a fresh food diet.
Now, as to your hope that he will continue liking all people as he is doing now... well, let me put it this way, if it was me, I would not count on it. Quakers are highly social birds which even nest in the communal nests they share BUT all the birds in that nest are related through their mothers so, in reality, they stick to family and don't like strangers.
I would hold on the training until after its first full molt. Not that this means you won't be teaching it anything - far from it! There are all kinds of things you will be teaching it - things like step up, step down, come here, go home (this is the command I use for them to go back to their cage but you can use whatever wording you prefer), gently (this is the command I use when they first come to me and they nip too hard), etc. It will also learn what Good Morning and Good Night means, good boy/girl (you need to have it DNA'd), bad boy/bad girl, and all kinds of phrases that will have specific meanings. Birds (and all animals, really) are like children. One teaches them the 'important' things they need to do in order to be well-behaved BEFORE they go to school so hold on the formal training sessions and just be consistent on your verbal commands and reactions and you will be surprised how much it is learning without you even trying!
One thing that is imperative with quakers: a strict solar schedule! Quakers come from a temperate climate and NEED the four seasons to stay healthy and happy (and for them not to become screamers and biters) so make sure it has full exposure to dawn and dusk and that the solar schedule is kept all year round.
Just as an FYI, blue quakers don't exist in the wild. I have seen, literally, thousands and thousands of them but never a single blue one!