expand thumbnails as defualt in embed API

The showThumbnails variable only turns on the appearance of option button in the right hand side menu bar NOT the actual thumbnails pane. It woudl be helpful to be able to specify this as default.

This is simialr to this already raised issue:

https://community.adobe.com/t5/acrobat-services-api-discussions/embed-api-expand-bookmarks-pane-by-default/m-p/13244766

We have also tried using the various save settings in Adobe Acrobat at the point of file creation, but these are ignored by the API.

1) Does anyone have a successful workaround for this ?

2) Can it be delieverd as an enhancement? 

2a) If so - whats the likley timeline... we are keen to migrate to the embed api in Q1 2023 for our client facing systems but we cant without this feature, which either means roll-our-own or move to another provider who supports this functionality.