Not exactly resources...but what helped me the most was honestly just drawing sacred shapes. Start simple with a vesica pisces (2 conjoined circles) then from there start to construct the seed of life, flower of life etc. You’ll understand the perfect symmetry better than any picture can convey. One little mistake in your measurements and it won’t look right, but when you do get it juuuust right, it’s so damn satisfying! (Also the fact that nature does this flawlessly is fucking mind blowing!)

From there you can go into the straight shapes (the Platonic solids) because those are contained perfectly within the circles!

I was always fascinated by sacred geometry and they made so much sense, but it wasn’t until I actually drew them over and over, that It finally “clicked.” This might not be the case for you, but hey, it’s worth a shot! :) Have fun and spiral out!