For everyone asking about the tasks syncing with planner, for me it looks like this feature is either not working great or some admin settings for syncing were changed since this post was published. This feature was working for me last week after using the steps in the post below to set up loop on a business standard account. https://techcommunity.microsoft.com/t5/microsoft-365-blog/learn-how-to-enable-the-microsoft-loop-app-now-in-public-preview/ba-p/3769013
This week when clicking on the 6 dot menu I do not have the "open in planner" option for new task lists. I have multiple task lists that were created last week that are still syncing properly between planner and loop even when adding new tasks or changing due dates on those lists. For those lists that are working after being setup last week sometimes the open in planner option is there under the 6 dots menu and sometimes it is not. I am the admin on the account and no settings have been changed since the original setup.