strong AF and sharp image quality in low light.

Sadly, u/shmallkined, autofocus is not Panasonic's strong suit. And the GH5s/GH6 are pretty good in low light, but the full frame Sonys are better.

For that reason, I recommend either a $3,498 new Sony a7S III or a $3,659.95 used Sony FX3.

And for low light telephoto shots, I recommend a $1,099 (on sale) Tamron 70-180mm f/2.8 lens. [Referrals]

Here is the image quality these cameras can produce in low light concert settings:

a7S III

• Mr. jones Concert Counting Crows | Sony A7S III by Arocapro (1080p - shot with Tamron f/2.8 lenses)

• BLESSD CONCERT LONDON | CONCIERTO LONDRES 2022 | SONY A7SIII by Briansalcedo4k (4K)

• Lil Baby Show 4K Sony A7S3 by Life Of The Shooter (4K)

FX3

• Sony FX3 Cinematic Benefit concert by Omar El Ramo (1080p)

• Sony FX3 - EPIC Concert Highlight Reel by Ben's Film Odyssey (1080p)

• GUS DAPPERTON + SPILL TAB | CINEMATIC CONCERT RECAP | SONY FX3 by angelllortiz (4K)

These cameras will give you the best combination of autofocus and low light performance in the $4,000 to $5,000 price class.

Hope this is helpful and good luck finding the right camera for your needs!