Since then Shopify has updated a bit (although not all that much, a lot of the issues remain) and we have had a wave of requests in the last year to build in Shopify - largely since none of the local marketing agencies want to touch headless.
It's been a bit disheartening really. I've been trying to get to the bottom of the marketing issues but I haven't been able to get clear answers on what they are.
Shopify also doesn't have amazing support for headless (double login on checkout is a big one), but with the rollout of their own Oxygen/Hydrogen platforms I've been waiting to see if they manage to solve these issues for their own solutions.