Hosting many Static Sites with Single Cloudfront Distrubation

Hello, i’m planing to build a SaaS Plattform like Shopify. part of my business will be that the customer can have their own domain on which their shop runs. I’ve solved everything on aws so far, but I’m now coming up against a limit (number of S3 buckets and the domain assignment). My principle when creating my platform was always that it scales from 1 to 10000 without resorting to servers or manually switching anything later in production. I found a solution here, where u use 1 cloudfront distro with 1 s3 bucket with multiple directorys : https://repost.aws/questions/QUJCmEN5YvTdevcBub9nlW5w/hosting-1000-s-of-static-sites

but i wonder what the limitation of ssl certificates has to do with it. without increasing the limit I can only use 10 domains with SSL? example.com shop.com test.com ... If so, what can the limit be increased to? Can it be that AWS denies my limit increase? I ask myself the same thing for domains in Route53, there I have a limit of 20, to what can this generally be increased?

Edit: i just found out about Amplify. this service seems also nice, i could use amplify for the static site generation and use 1 s3 bucket with all the images. but it also has a limit of 25. does anybody know how much i can increase the limit?

I also can not find anyway of explaining my limit increase or contact the support. it would be really nice to know beforehand what limit i can expect before building my plattform and than later to change it again because of the limit