Indeed, of course Simple Delivery is unsatisfactory! It isn't simple!!

The ironic thing is, Vinted have something very similar but have pulled it off perfectly! Seller chooses (at an account level) what couriers they want to have active, and the buyer then chooses exactly what service they want to use. Evri? Yodel? InPost? Royal Mail? Any of those is fine - even DPD is fine. And most importantly - the buyer sees the options (either pickup point collection or home delivery) and chooses which they want to use from what is available, with prices showing at checkout based upon which option is selected. Couldn't be much simpler!

eBay's Simple Delivery is so unfit for purpose, I refuse to use it. If a private seller is using it, then that is fine, as both Evri and Royal Mail are fine in my area (and the money back guarantee is there for if Evri smashes something up). But as a seller, I will not use Simple Delivery. And that IS simple.