If I prune off all of the new growth on my apple tree...

suggest you look at the RHS pruning made easy webpage https://www.rhs.org.uk/advice/profile?pid=90

that's the way they grow. the fruiting spur develops over the summer. if the tree is too big remove some of the larger branches leaving fewer fruiting buds.

RHS will tell you in detail. But first you need to know whether your apple is a tip bearer - has fruit at the ends of the branches - or a spur bearer - has apples along the branches. The idea of pruning is to create lots of spurs - the fruiting cluster - along the branches. But not to let all the energy go into long shoots that you can't reach anyway. Prune the new growth back to almost last years - allow 1-3 more spurs in summer - that will mean the energy can go into the spurs left so they flower well in spring. In winter prune out damaged, diseased, crossing branches - and shorten any wayward branches as you did in summer. Some varieties are very quick and energetic and need a lot of pruning, some need barely anything.

Just to show - I have Braeburns growing as stepovers (just two long branches grown out along wires) which are on a vigorous rootstock and I tend to prune them 3 times, twice in summer and once in winter. But a Court Pendu Plat I have on a smaller rootstock and I grow as an arched cordon - I just snip the odd branch back. They are just like people - contrary!

Thanks for the advice, it is very good. I had in fact already visited the RHS website, but I had not noticed the section called Winter regulated pruning.