Do we have to use shopify shipment to have transit time?

Hello all!!

Thank you in advance for reading my post.

So for the past year, we operated our business by shipping everything directly from our warehouse in China.

So, what I did was set up a location in China in the backend, as shown below. As fulfill orders from this location.

Because Shopify shipment does not cooperate with any carrier in China, when I want to add a rate for this location, I do not have pre-set choice from carriers, but have to create my own (below)

This has been okay for the past year because we fulfill orders only from this location. So all I have to do is to have a shipping policy and then make it a link at check-out. Simple and nice.

However, now this year, I want to show the expected delivery time at check-out, rather than a link to the shipping policy. To do that, I need to have transit days as shown below, which I don’t have if I use my own rate.

So this kind of goes into a dead loop. To show the expected delivery date → need to have transit days. To have transit days → Need to have carriers in location. but the China location does not have a carrier, and creating my own rate is the only option, and it does not have transit days…

This brings my first question: How to make transit days for this location?

Further, this year we create a second warehouse in Canada. While I try to create a rate for that location, I see this:

As you see, there are pre-set options, which are Shopify shipments. This brings my second question:

It seems if I do not cooperate with the shopify shipment, I cannot show expected delivery date at check-out due to I don’t have transit days. So, how do I make it show up at check-out, while I have my own carriers and calculated delivery dates?

Thank you for reading this all alone and all your help is appreciated.

Best,

Sam