Maybe keeping your chapter active on social media is not the right fit, or enough, for you.
You are free to create a website for your chapter, you could ask other organizers what their experience with tools are.
Here are some examples of chapter websites for inspiration
Maintaining a single website for a whole country can reduce maintenance efforts. Example: R-Ladies en México.
Furthermore, if you list the contact information of all chapters, it might mean a potential external collaborator might contact all chapters at once instead of e.g. only emailing the chapter in the capital of the country.
You can also use it to promote inter-chapter activities.