As a counter-point, IG recently made it much easier to upload content directly from a desktop operating system. It finally added a button for users upload posts from a web browser from a desktop OS (before, you had to switch the browser's user agent to identify as a mobile device, then refresh).

But separately, if professional brands really do take over IG over user-generated content between friends, the runner-up is Pinterest. A February 2021 study of social media usage shows that Instagram usage among US adults is 40% [0], with Pinterest at 31% usage. Beyond Pinterest, the runner-ups for (high-quality, artistic) creative content are platforms like Adobe's Behance or Dribbble, but the users for these are primarily creative professionals.

For user-generated content between friends (day-to-day stuff), Snapchat isn't a bad replacement (25% usage, according to the same survey). I would guess that most content remains user-generated (via photos that delete themselves sent to other friends). I would also guess it's less less harmful to mental health for certain groups, as it doesn't feature Likes or Comments.

To be totally honest, though, I wouldn't regret the loss of user-generated social media content. Exchanging messages, having video calls, and seeing people in-person feels a lot more enjoyable and helpful for strengthening relationships.

[0] https://www.pewresearch.org/internet/fact-sheet/social-media...