Active Storage to Digital Ocean Spaces

I am trying to upload a file to spaces and make it public programatically, without changing any settings in DO dashboard but it does not work. All uploaded files are private by default.

I found that there is a public setting added to active storage:
https://edgeguides.rubyonrails.org/active_storage_overview.html#public-access

which is available in Rails 6.1.0rc1 . I tried that but it still uploads files as private. 

Is there anything needs to be changed in direct upload javascript for this? Or is there any API call I can make at controller level?

I'm going to be doing this shortly as well, but haven't done this before...