I would like to able to block the complete .io domain or at least

Via Parental Control I blocked the categorie 'Games' but it does not block all the .io games that my kids keep finding ;-) I tried blocking them via websites, but thats very inefficient because there are way to much .io games/sites to filter them one

What is a parked domain name?

What is a .IO Domain, And Why Should You Consider One?

Domain Extensions: .com vs .org, .net, .io & 4 Other TLDs (Study)

What is a .IO Domain, And Why Should You Consider One?

How to Choose A Dot Com Domain Name Alternative

10 Most Popular Domain Hacks - OnlyDomains Blog

Domain Name Search – Check Available Domains

1push.io

Choosing the Perfect Domain Extension - DreamHost

Energized Ultimate lists blocking NextDNS - Bug Reports - NextDNS Help Center

Using multiple nodes

You Can Now Remove GDPR Blocking at Enom and Tucows

Email Deliverability Best Practices