Hi diyaaa
I understand that the question is not whether "ATUM" supports this, but if "ATUM Multi-Inventory" supports this, am I right?
ATUM plugin does not have any conflict, but with ATUM Multi-Inventory, you can create as many custom inventories as needed. But the Yith plugin is only able to read and write to the WooCommerce default inventory. That, in our case, is linked to the main inventory.
So, if you set the main inventory as your "POS" inventory and create a separate one for your "other" stock, perhaps it could work, but we have not tested it. You should confirm this yourself.
If this doesn't work, they are not compatible.
Best Regards,
Salva.