And for colored Sacks from Supplementaries Squared?
As well as tooltip preview, all while having Shulker Boxes only have theire contents visible on the inventory, while having o place them to take them out?

How can i add Bundle-like compatibility for Sacks from the mod Supplementaries? And for colored Sacks from Supplementaries Squared?

Hi! You'll need to implement and register an InventoryViewer for each of those items. You can check out this example for guidance.

However, I'd recommend leaving that to the authors of those mods.

while having Shulker Boxes only have theire contents visible on the inventory, while having o place them to take them out?

Set validation.minecraft:shulker_box.enable to false in the config.

@Kir-Antipov
Is it not possible to have your mod allow compatibility using Datapacks or some config?

Yeah, no. When I first started this mod, the whole data-driven haze hadn't really taken off yet. Additionally, it's not possible to make this mod fully data-driven, as different custom containers provided by other mods often don't adhere to common implementation guidelines, which would still require in-code compatibility adjustments.

However, I do plan to introduce at least some level of data-drivenness to Packed Inventory once I finish refactoring it. This way, at least some common scenarios will only require a JSON file for setup.