Bundle products (500 options) loading very slow

[schmeeshepcfb8]

Hello, I have a bundle product with 500 options (all input=radio). The shop page (frontend) takes 80 sec to load, the products/catalog/product-edit page (backend) takes 50 sec to load.

On the shop page I found out that the problem is the name attribute of the input type="radio" of the options. It is an array like name="bundle_option[3453]". When I edit the radio.phtml and set name="bundle_option[]" to all options, the page loads in 2 seconds. 

I found another magento website which also has hundreds of options using this array but that page does not load slow. So there must be a solution for my problem. Can anyone help?

My config: Magento 2.1, All cache options enabled

[schmeeshepcfb8]

On the shop page I found out that the problem is the name attribute of the input type="radio" of the options. It is an array like name="bundle_option[3453]". When I edit the radio.phtml and set name="bundle_option[]" to all options, the page loads in 2 seconds. 

I found another magento website which also has hundreds of options using this array but that page does not load slow. So there must be a solution for my problem. Can anyone help?

My config: Magento 2.1, All cache options enabled

[schmeeshepcfb8]

To be more specific:

The product website loads fast but the product image and the bundle options take time to load - there's an icon instead of the content (loading circle).

I have now activated "bundle JS" and "merge JS" in the "STORES / configuration / Advanced / Developer / Javascript Settings" section. Now it takes 10-20 sec to load the page - better than before but not fast enough. 

Does the "Minify JS" option save some more seconds when switching to "production mode" (i use developer mode at the moment)?

I don't know if moving the JS from header to footer is an advantage in this situation. Does anyone have a tip?