I believe you could install VS on a Virtual Machine and take a snapshot as soon as you have signed in successfully. If you get to a point where the software no longer functions without a license check, then you can revert to the snapshot. You would probably want your code on a separate virtual disk or it will be easy to accidentally wipe everything. Version control is going to be a challenge in an offline environment that you should start thinking through now.
I would imagine that you would have greater success finding a solution with Professional/Enterprise version. The Community edition is not aimed at corporate developers, and if your company has > 5 developers, you might be breaching the EULA already and need to buy commercial licenses immediately. If you're a startup, Microsoft has some programs that will hook you up with software, but most of it is Azure-based which doesn't help you.
I would think that with the Enterprise license, Microsoft would be willing to help you deploy a Key Management Server solution. KMS is used for volume licensing with Windows and Office, or rather was used prior to Office 365 and the cloud era), but it would allow you to validate your license in a Microsoft-approved manner. If you have a client success manager or sales engineer you can reach out to, that is likely your best bet to learn about options.
You could also look into JetBrains Rider, which can use a text-based license. It's more geared towards .NET Core, however, so it might not meet your needs.
Are you at liberty to discuss the HW limitations in greater depth? I am wondering if there are CI tools which could help you deploy. If all else fails, there's always Sneakernet to deploy data.