Yes, it works. The most interesting nuance is that Instagram still analyzes the metadata of your videos, and you can upload one video from TikTok to any number of Instagram accounts without any processing or issues, while still getting views. So, you take your video from TikTok, download it using any convenient method, such as Snaptik, and upload the content to Reels — done! Both platforms have quite similar trends and similar sounds, so the video you create on one of them will be relevant for the other.