I hear ya. High iron in our water, too. I’ve used straight bleach and it take hours to get rid of the stains.
I turn off the water and totally drain the toilet after a regular cleaning and then use a large sponge on a stick to sop up any residual water. Then, pour in Lime Away or anything similar at full strength and allow to sit. After several hours, scrub again. I still had to use an old serrated knife to get the last of the iron deposits off down at the very bottom.
Most hated job.
Try heavy duty oven cleaner on the dry parts (hold breath till out of area), let sit for a while b4 scrubbing. And try Ultra Clorox on the other (be careful not to get it on your clothes), preferably when the bowl is empty.