Under your repository name, click Settings.
If you cannot see the "Settings" tab, select the dropdown menu, then click Settings.
Under "Default branch", to the right of the default branch name, click "Switch to another branch" beside "Rename branch".
Select the branch name from the dropdown list and select "Update".

Thanks for posting in the GitHub Community, @vathanauplight ! We're happy you're here. You are more likely to get a useful response if you are posting your question in the applicable category, the Discussions category is solely related to conversations around the GitHub product Discussions. I've gone ahead and moved it for you. Good luck!