Help with SMB mount - can read/delete but not write

Hi all, I'm so confused about what I'm doing wrong and couldn't find any guides/troubleshooting for my specific problem, so hoping someone here can help.

I'm setting up a new Proxmox server and trying to share a folder between 2 Ubuntu VMs - a "Fileserver" VM running the SMB server and a VM that I will be running docker on ("docker VM")

my smb.conf on the fileserver:

[pool]
     path=/mnt/mergerfs
     read only = no
     browsable = yes

my fstab entry on the VM running docker:

//192.168.0.20/pool     /mnt/pool       cifs    _netdev,credentials=/etc/.smbcredentials,uid=1000,gid=1000      0       0

On the Docker VM, I can see that the folder is mounted properly with the correct permissions for the uid/gid specified (dockeruser) and with 755 permissions, but I am unable to write to it with either dockeruser or root. Interestingly, I am able to DELETE files on the share, which is confusing the hell out of me.

If I mount is as root (no uid/gid arguments in fstab), I am able to write to it, but for "best practices" I'd like to get it working with a non-root user. Any ideas?