I've been with Shopify since 8/2020 - using the Default Shipping. Is it just me, or does Shopify Default Shipping now offer the vast majority of the services that the Apps advertise?
For example Default Shipping offers: Tracking notifications to customers, offering multiple carriers in the shopping cart, discounted (cubic) rates, Abandoned Cart recovery, etc.
The main feature I really need is something that memorizes the correct Box Size for each order. For example, an order for 1 Body Lotion should go out in a 6x6x3 box every time and ship with shipping options selected by the customer every time - rather than making me choose the box types and shipping option for each order.
Can Shopify Default shipping do that? Or is there an App that does?
Yes, if you are in the US or Canada, and use the main carriers like USPS, UPS, etc, Shopify allows you to send tracking notifications to customers. Shopify also allows you to get discounted rates from these carriers.
Regarding your query, if you have not found a solution to this, the Multi Carrier Shipping Label app can help you with this. You need to configure your own carrier account with the app, and the app allows you to display rates at the Shopify checkout (provided, carrier calculated shipping is enabled in your store). Along with this, you need to choose the Box packing method available in the app, you can add custom boxes based on your products and the app automatically chooses the right box based on the customer input at checkout.
So, the app automatically chooses the service that the customer has selected at checkout and select the right box configured by you based on the order.