In my original DNS and Bind book. When people used to look after their own nameservers, it mentions the idea of farming out subdomains in a trusted community spirit.
As such ask a friend to point a subdomain your way.
And if you were to add your domain to the public suffix list (https://publicsuffix.org/) it would effectively be treated like a domain name rather than subdomain name within browsers for JS security, etc.
You'll notice that myshopify.com is on there... effectively allowing subdomains of that (customer specific, each customer does not trust other customers) is now treated like a domain so that customer1.myshopify.com and customer2.myshopify.com are both isolated from each other by apps and systems that utilise the PSL (all major browsers, etc).
You might divide that namespace greatly. The one higher up the pyramid still isn't paying 100,000 whatevera a year. In the main the vast majority of users don't give a rat's arse about the domain. But they do have trust issues. Webs of trust can ease this. And relieve you from the scam world of vanity TLDs and overpriced digital number plates.
And if you were to add your domain to the public suffix list (https://publicsuffix.org/) it would effectively be treated like a domain name rather than subdomain name within browsers for JS security, etc.
For example, if you look at the list: https://publicsuffix.org/list/public_suffix_list.dat
You'll notice that myshopify.com is on there... effectively allowing subdomains of that (customer specific, each customer does not trust other customers) is now treated like a domain so that customer1.myshopify.com and customer2.myshopify.com are both isolated from each other by apps and systems that utilise the PSL (all major browsers, etc).