Fellow G7 user here. Honestly, I would use the money toward better glass, lighting, etc. Now this all depends on if you don’t already have these. But if you don’t, or have them but they are lower end, consider going this route. Maybe by an 18-35 and viltrox speedbooster, and an aperture 120d or something. I’ve been tempted to upgrade my g7, but I’ve decided investing in hq glass and lighting is a better investment.
If you are fine with lighting and lenses you have, I personally think that your next camera really depends on your shooting style. Doing turn and gun? Need a complete, ultra-reliable package with great IBIS? Gh5/G9 is for you. Don’t need IBIS and want larger sensor/better stills? XT3 for you. Really we can’t determine this for you. It really depends on your shooting style.
Honestly I still think the g7 is fine. I would invest in better glass and lights. You will notice more improvement there.