Mobile Help needed on fighting the mechanical bosses - Mobile 1.3

[Build]

Welp this is the second time writing cause first time I checked the spelling of "Daedalus" and it reset my entire draft so let me just not beat around the bush and just state my situation without going into much detail.
So I've been trying really hard to beat the mechanical bosses and I've been at it for a day or two without any real progress. I've already fought the Destroyer 5 times, the Twins twice and Skeletron Prime once, with all of my attempts unsuccessful. Here is the gear I've been using for the fights:

My gear is pretty advanced stuff for a pre-mech boss player, I've come to realise (Well maybe not the accessories as much) yet I still can't seem to make any progress with the fights. You might say I just suck and yes, maybe it's true. But I've gotten this far and I'm really determined to make it to the very end. My arena consists of a stretch of cactus platforms around 300 blocks wide and 3 levels in terms of height with around 6-10 blocks in between each one. There's a campfire somewhere in the middle and a heart lantern at the very far right of the arena. I usually fight using the Blessed Apple aka Unicorn mount with the Gatligator-Exploding Bullet combination or the DAEDALUS Stormbow-Holy Arrow combination, enhanced with the potions; Archery Potion, Swiftness Potion, Heartreach Potion and of course Ironskin Potion. Yet all this seems to be in vain as I can't even get the Destroyer to half his health! I'm not even in Expert mode! I must really not be very good at fighting .
Help would be GREATLY appreciated, thanks!
PS~ If I missed any details you'd like to take into consideration, let me know.

 

[Buffling]

If you have a nimbus rod, clockwork assult rifle, megashark, or daedalus stormbow( Clockwork assult with nimbus rod is best) the destroyer should be very easy. Make a rope that goes high up, build a box with a mostly platform ground and just shoot down at him. If it is high enough up, he won't be able to reach you and hopefully you can take out his drones easily enough.

Once you can kill him, you can farm him for hallowed bars. With hallowed bars and his souls of might you can make the light discs, excalibur, and a full set of hallowed armor if you farm him enough.

His boss summoning item is not very hard to make, so you could farm him pretty easily.

 

[Dapling]

It's best to fly in a diagonal pattern raining down arrows for mechs rather than try to use your unicorn. Also, you can try upgrading your Anklet of the Wind to Lightning Boots.

Frost armor is also very very bad and should never be used in any playthrough. Use titanium, orichalcum, or palladium instead (if you can afford to choose between them, titanium is the strongest, followed by palladium then orichalcum.) Palladium and Titanium are actually so good that it's highly likely you'll have better luck with them then hallowed armor after you've killed the mechs.