Sure sounds like Wish marketplace is in a death spiral. To be clear, I'm sure I am not the audience for the site. Invested in better logistics, but didn't pan out in higher retention or increased purchase rates. Instead, these metrics declined.

Either they are fooling themselves that logistics is better, or they are expecting their audience cares about logistics when they don't - they just care about a deal.

Revenues off, so they pulled back on digital marketing. Which will reduce their traffic. This is almost the definition of a death spiral.

Repeat after me. You can't fill a leaky bucket. This cuts across all areas of your customer experience, but it starts with your product and presentation, and follows through to operations and delivery.