I have a row of about 10-13 that I started from various storebought apples (seed) a few years ago. I really need to get my “orchard fence finished and get them into permanent locations. Trying to get rid of my surplus, I posted them (and my grafted ones) on social media and, given their stigma, was surprised at the demand for the seedlings.
They grow fast from years 2 on.... if you or nature don’t kill them. I definitely have fireblight and cedar apple rust present, but most of the trees have shown resistance.
Careful with the pruning! For me 20/21 was a mild but testy winter due to some intermittent and late cold snaps. Now after the fact I have seen writings about pruning timing in cold climates (z4) and I’ll wait till March instead of Jan/Feb. Seems that mid winter pruning isn’t a good idea here. It stimulates a healing response which kind of pulls the tree out of dormancy. it got down to zero after pruning and I had noticeable death or dieback on trees/whips that I had worked - including some of the prized seedlings that I was trying to shape for fruit bearing. Things are taking shape, but 4 years here and I can’t seem to grow anything except flowers on my fruit trees.