AnyStream does not "support" VPN, simply because it does not need to: once a VPN is installed and active on a OS, all applications on a computer are using this VPN as default gateway, so does AnyStream - there is no other way "out". But AnyStream does support proxies, since a proxy does not act as default gateway - each application has to redirect the traffic to proxyip:roxyport by itself.
And yes, most streaming services try to determine if your are using a VPN, TOR or proxy. Some are more picky with it, some don't care. The reason for them to find out if you are using a VPN/proxy is not the "evil" AnyStream, it's just about "geo blocking". Licenses for content are always bound to regions, like North America, Latin America, Europe. They can be bound even to countries like Italy, UK, ecc.
So depending on the license agrrement a streaming service signed with a content provider, they are not allowed to give you access to content of another country.
Determine the type of the IP address (data center host, VPN, proxy, TOR, business, relay, residential IP) is super easy, the use services like maxmind.com or ipinfo.io, or they have their own database (Prime has this for sure). Technically, only residential IPs should be allowed. But there are also VPNs and proxies using residential IPs.
Here a list of free proxies you can use, I suggest to pick one with SOCKS5 protocol:
https://geonode.com/free-proxy-list/
Examples to determine the ASN type of an IP address:
https://ipinfo.io/91.121.109.60 (a proxy server from the list above hosted by OVH in France, flagged as "Hosting" )
https://ipinfo.io/14.226.9.188 (a proxy server from the list above in Hanoi/Vietnam, flagged as "ISP". This would be a perfect proxy if you are looking for content in Vietnam
)
https://ipinfo.io/32.221.142.20 (a randomly picked IP address in the US, flagged as "ISP", which is a residential IP)
However, finding a non-blocked VPN/proxy is a daily challenge. Even if you found a working IP of any ASN type, it could/will be determined by unusual high traffic from one IP with different accounts, and blocked...