Support with Moblie Crashing

I’m developing a new site and it’s quite media heavy, I’m struggling with consistent crashes on mobile. Both safari and chrome and all different types of IOS devices I’ve tested. 

I’ve got some custom CSS enabled at the moment but I’ve tried disabling and the issue is still there. 
 

https://goby-disc-7f97.squarespace.com/

Password is reviewwebsite

Really appreciate it. I’ve attached a video of the issue too. 
 

you can see in video the scrolling is fine and then the video background stops and the entire site stops working  for about 1 min and then content normally comes back on

Do you have a gauge on how large this page is? Images should be under 500kb and video should be less than 30 seconds. Perhaps that's the issue? Have you checked to see if this is a known issue with Squarespace? 

Hello! There is a fair amount of media for sure - all the videos are either added via Vimeo or direct into Sqaurespace. Image wise they will be bigger than that I'd think! Is there a system at all that can look at the size of a page?