Noticed you are considering suspension seat post from AliExpress shipped from China. Have you had any experience buying bike parts on Aliexpress before? It's a lot cheaper there but not sure how much I trust it :).
Super helpful...thanks! One of the Ride1Up reviews on Youtube really raved about the phone mount available through Ride1Up in case you want to put that in consideration as well:
https://ride1up.com/product/phone-mount/