I've stopped using hairspray, as I agree it makes it feel crispy (I've got the Cheryl one too) and whilst I use it after a blowdry or on my roots if I've used the Babyliss Root Boost, I don't use it for my everyday waves. I find it makes the waves "messy" after sleeping on them if they've been sprayed, whereas if I haven't then they say soft and well formed and if they get a little messy a light brushing reforms them (sometimes I will re do the topmost layer)
I suggest you keep trying various brands till you find one that suits. I think there's always a temptation to buy "firm hold" because you feel you are getting more hold for your money but perhaps a light hold one will do enough without turning you crispy.
Your highlights. I think the problem is, in order to stop the block blonde effect we have the lowlights, but it all just becomes a bit pointless after a while.
I suggest to achieve that lovely streaky root to tip look is you start from scratch. Dye your hair a dark ash blonde (do a strand test first - you don't want to go too dark nor do you want to lighten your base colour - just achieve a good natural similar to your real hair base) - so you are "starting again". Don't be tempted to go too dark, nothing "brown" if you have been bleached, but Dark Ash blonde or even Beige Blonde should be fine. Book yourself in for a full head of bleach highlights, and do the "redying" the night before or a few days before if you can bear it and are confident you wont hate the block colour for a few days. Then have your full head of highlights. They should be lovely and streaky looking from root to tip, very pleasing on the eye, because the streak starts at the root and goes all the way down, breaking up the base colour. Then buy a purple shampoo like the Lee Stafford Bleach Blonde one and use that occasionally to really "bring out" your highlights.
The next time they need doing, have a half head. Try not to be greedy and get them done too soon, the more often you do them the more they start to join up and you start having brown put back in and it all goes a bit mish mash.
But you could probably "start again" twice a year, once in the summer and once before Christmas, where you dye yourself back to your base colour and have a full head, to achieve that root to tip streaky highlight look. You might find your hairdresser is a little adverse to this because they wont want you to start getting involved, but it sounds like you are not happy anyway - maybe a change of hairdresser.
But I basically did this myself in the spring, I had gone light ash brown, and had a full head of bleach foils, and it achieved a really nice stripey streaky effect. Tell your hairdresser that you want to be quite blonde and that you want the highlights to be bleach and that you want that streaky effect - communication is key, as some people want really fine undetectable highlights and others want a nice streaky look.