Syncthing permissions question

Hello,

I'm new to OpenBSD and I'm unfamiliar with permissions in general so I'm
a little lost. I installed syncthing, and it creates the default folder
in /var/syncthing/Sync which is owned by _syncthing and has the group
_syncthing.

I'm able to read the contents of the directory, but I'm unable to write
into them. I tried adding myself to the _syncthing group by doing:

usermod -G jag _syncthing

But it seems that I'm still unable to write to the directory. I know I
can change the ownership of the files by using chmod -R, but new files
will still have the same _syncthing user and group and it seems off to
keep changing permissions of the files.

How do I enable the user `jag` to read and write to things owned by the
daemon `_syncthing`?

Thank you so much!