Can there be problems copying files from AFPS to other file systems? I have a simple question: I bought a NAS from Synology and I copy my files from macOS (my filesystem is AFPS) to the NAS with Samba, formatted in ext4. Sometimes I also copy files from AFPS to NTFS (I'm using the Paragon Software). I never had any problems, but I want to be sure: Can there be problems due to these different file systems for example that files won't be copied, because the target system doesn't support the filename? macOS would tell me, if this is the case?
Files content is just bytes and the FS job is to handle it and that's all, by copying a file you just copy the bytes and not how it being handled. SMB send the data as a raw data and the "other side" receive it as a raw data and handle this data according to it's rules.

So to answer your question, the FS does not matter.