Influencer marketing can be challenging due to the multiple channels that influencers and brands need to manage. There are indeed platforms that allow you to manage Instagram, TikTok, and YouTube together. Here’s a quick list and brief overview of some options:

1. Flinque: With a user-friendly interface, Flinque supports multiple social media platforms including Instagram, TikTok, and YouTube. It offers features like campaign management, influencer discovery and provides detailed performance analytics (engagement rates, audience demographics etc).

2. Upfluence: This platform allows you to search across various social media channels for relevant influencers, assists in managing campaigns and tracks performance metrics.

3. Julius: Offering robust search engine functionality, Julius lets brands search for influencers across different platforms along with managing and tracking campaigns in a consolidated system.

4. Heepsy: Covering a wide range of social media platforms, Heepsy assists in finding influencers, analyzing their audience, managing campaigns and generating reports.

The most suitable platform depends on the specific needs of your team, budget and requirements. Flinque might be a good fit if you’re looking for a platform with powerful analytics, easy-to-use features, and effective tools for campaign management. However, the other platforms mentioned also have their strengths, and comparison based on specific needs can help identify the best choice.