If on the landing page is not a single word on shipping time. Wouldn’t that put off quite a lot of people by not knowing the expected shipping time frame?

Shipping of 10-20 days is ok. We notify customers through an order confirmation email and give them a chance to cancel their order if they don’t want to wait. Only a very small percentage of people cancel their orders. As long as you are transparent and communicating with customers you wouldn’t have issues.