Videos are not loading for some users

Hello,

Videos are not loading for some of our users. We are using the latest account-specific subdomain.
Can we use CNAME of our platform’s subdomain instead of customer-xxxx.cloudflarestream-com domain which still few ISP are blocking?

I would also like to know if it’s possible to use a custom domain for the output (I see it currently is for input, via the live inputs settings).

Whether that would involve a CNAME to customer-xxxx.cloudflarestream-com (in DNS, like for the live input).

Or using a Worker in front of it? Or somehow using R2?