All subscription types have equal functionalities. Consequently, your VM will run equally well with each of those.
If it is critical that your Proxmox VE server and your VM continue to work and that you get guaranteed support then I'd suggest getting at least BASIC. While we try to answer as many posts in the forum as possible, we can only guarantee answers for subscribers asking in the Customer Portal. This is available for BASIC or higher. If you need really fast responses, then STANDARD or PREMIUM are an even better choice.