Can’t be done on a single share basis.
Due to the security implications associated with having SMB1 enabled, I suggest an alternative approach: duplicate the content on a spinner that is attached to a RPi, Apple Airport, or like lite-duty “NAS“. Then, if it gets nuked, oh well, now you know you have a problem in your network (ie honeypot)
that’s how I keep my music for the Sonos as the Sonos way is insecure for anything that they’re not required to secure by content providers. From what I have been able to gather on the Sonos forums, despite the S1/S2 Firmware split, SMB2+ is still not available on either.
if this external drive has to be semi performant, consider marrying a RPi with a leftover mSATA / NVME Drive holder (see geekworm), use Ubuntu server and bcache to fuse the SSD and the HDD. That’s what I’m slowly setting up as a time machine target for my kids. Low power, separate from the server, good enough for their use case.
my laptop then periodically synchronizes these external units with the server. Not yet certain how I will do it re: the TM share as that is a different VLAN. Most likely, makes sense to configure that as a plug-in USB adapter that is only used for that application. Not air-gapped, but close.