The GH6 has the same USB power capabilities introduced in the GH5M2.
In this video I show you what I use with my cameras.
Initially with the GH5 I could only use a dummy battery kit and this will continue to work however it may have challenges with mechanical shutter or very high bitrate codecs of the GH6.
Therefore the recommended solution is a PD Power Bank
Pay attention to the checks you need to do as your power bank needs to deliver 9V 3A which usually means at least 45W better 65W
US
1. Dummy battery kit: https://amzn.to/3sFarxp
2. 65W PD Power Bank: https://amzn.to/35Kh6gW
3. Cheap USB Power Bank: https://amzn.to/3IVhM1u
4. USB C Cable: https://amzn.to/3tnsreQ
UK
1. Dummy battery kit: Currently Not Available
2. 65W PD Power Bank: https://amzn.to/3KgGfih
3. Cheap USB Power Bank: https://amzn.to/3HBGDGk
4. USB C Cable: https://amzn.to/3sGBmcj