front carrying 6l sling

Ill be doing a lot of traveling by train this summer, and will be bringing some entertainment during transport, specifically a steam deck.

I was initially planning on only bringing my 28L Thule Aion backpack, but with the steam deck, the packing is getting a bit tight.

I usually travel with a sling, maybe a aer day sling 3, but im thinking of upgrading into a larger sling, something that could fit:

• A steam deck, with a skull and co grip.
• A kindle
• Travel documents
• Umbrella
• A small bottle

Im looking at:

• rework toshling 6l
• Aer Day sling Max

But since I will be carrying a backpack, I'm wondering if it's viable carrying those slings forward facing, like a front carry. Will it feel clumsy walking around an en entire day with a backpack and a 6l sling forward facing?