So, let me understand you correctly.
You failed to have any type of quality surge/lightning protection ( like a good quality uninterruptible power supply with surge and lightning protection) on any of your computer equipment, no backup drives with copies of your data on the backup (to guard against any type of computer failure) and your blaming Apple for frying your computer and you're never going to own an Apple computer, again???!!!
The fault lies with you and not Apple. There are precautions that you could have/should have taken to guard your expensive computer and peripheral equipment from being fried from lightning or a power surge.
As far as being able to get parts for your iMac, this is not possible as Apple doesn't sell parts to its customers. Apple only sells parts to its authorised dealers or repair centers. I do not believe you will be able to acquire/purchase any of these parts from a Apple authorised repair center, either.
If it is possible, you'll pay full retail price for these parts.
Are you even capable of working with computer electronics? This is not a simple swap out/swap in procedure to do what you are trying to accomplish.
Your only chance maybe would be to try eBay and look around to see what may be available for your iMac.
Other than this, you are basically screwed as even if you had the extra 2 year extended AppleCare warranty, I do not think the warranty covers damage from electrical surges or lightning.
This is why you needed to purchase additional electrical protection devices to protect your expensive Mac purchase.
Without this type of electrical protection, NO computer, EVEN A WINDOWS PC, would not survive a serious electrical surge/spike or lightning strike.
And, if your videos and pictures were that important to you, you should have made backups either to optical CD/DVD discs, USB Flash Drives or externally connected hard drives that you, also, needed to purchase.
This is a very expensive lesson that you have learned.
All of this stated, I am sorry that your Mac got fried from an electrical spike and you lost all of your data.
😟
