You should always ask in livechat to see if a casino is VPN friendly. Personally, I have the impression that more and more casinos don't mind the use of a VPN, I know some bigger casinos don't like it but I know of multiple casinos where I can use a VPN without any problem.
There is no need to contact customer support for this, actually, as it’s clearly stated on their home page that:"Niyvi.com – No KYC Withdrawals,
VPN Friendly & Exclusive Bonuses!"
I doubt their live support would tell you otherwise.
They are kyc-free and they are planning to create or become a completely decentralized casino, so I don’t see why they would prohibit the use of VPNs or any other tool that enhances users’ privacy!
Most casinos don't even border about VPN usage, especially the cryptocurrency casinos that we have around, to be honest with you guys, I have been using a VPN on a few occasions and I have not come across any problem while using a VPN the only problem is that while playing with a VPN my network speed is always affected and the site may not load as fast as it used to be, but aside from that, I have nevermind hard any issues with my account or funds before, a lot of time we tend to think that it the usage of VPN that brings those problems that gambler faces sometimes, but the truth is that they may have committed other offenses on the casino while using it and will not come out to accept that fact, so ultimately VPN have fewer problems for casinos most especially those that claimed to be KYC Free casinos.