What you are describing is called a Samba Usershare. Gnome, KDE, MATE ( with the addition of a package ), and Cinnamon have such capabilities. XFCE does not. You will have to create a classic samba share instead.
The following is an example of how I ( morbius ) would create a guest accessible share of my Public folder:
Install samba:
sudo apt install samba
Edit /etc/samba/smb.conf and at the end of the file add a "share defintion" to the Public folder:
[Public]
path = /home/morbius/Public
read only = No
guest ok = yes
force user = morbius
Then restart the samba daemon:
sudo service smbd restart
A MacOS client will be able to discover this server and it's share by default.
If you want to be able to discover this server and it's share from Win10/11 add another package:
sudo apt install wsdd
Discovering then accessing this share from another Linux client will be an issue. Not sure what else is on your network so I don't know if you have any Linux clients.
You could ether state the server and it's share from the Linux file manager. Something like:
smb://xubuntu-host-name.local/public
Don't forget to add the .local part at the end of the host name.
Or do a CIFS mount which I can explain if needed.