Sounds as thought you are where I was a few years ago. Lots of good advice from this forum has improved things immensely.
I also have some summer apples that make cider which lacks flavour, possibly because the sugars are eaten up by the yeast through rapid fermentation. The issues to deal with seem to be...
- Warmer temperatures result in very fast fermentation so the flavour gets 'blown off".
- Choice of yeast... i.e. EC1118 rattles through whereas WLP 773 was quite slow (and finished above 1.000)
- What can you add to help with the final product. i.e tannin, hops, non fermentable sweeteners etc.
I have had some success with early apples by adding other fruit such as cherries or pears to secondary. The sorbitol in pears results in some sweetness which compensates for the dry tartness that you might otherwise get with rapid summer fermentation.
Have fun, it is all good, but as my Grandpa used to say... some is better than others.