[2023] Used Physical Copy

My boyfriend and I bought TemTem when it was on sale a while back to play co-op together, however he's going to be visiting his mother for an extended period of time and will be leaving his PC at our apartment. I was wondering if because we have the full version on PC if I could get him a used physical copy for his switch, and set it as his secondary device for cross platform play. I keep reading about "TemTem Plus" for Switch which is made to prevent physical copies from being reused for free accounts, but I was wondering if that would even impact us since we bought the full PC version. If anyone knows for sure or could point me in the right direction I'd appreciate it, thank you in advance.