Powering this rig (photo inside)

Over the last few months I’ve put together this set-up:

Consisting of:

• Gitzo Series 3 Systematic GT3531S tripod
• Gitzo GS3321V75 75 mm bowl adaptor
• Miller Air fluid head
• Sound Devices MixPre-3 mixer and recorder
• Panasonic GH5S camera
• Olympus 12–40 mm f/2.8 lens (among others)
• Rycote InVision On-Camera shock mount when the mic is on the camera like this
• Rode NTG3 shotgun microphone
• Audio-Technica ATH-M20x monitoring headphones.

I’m pretty new to this game, so getting this far has already required much research and trial and error. It works pretty well, but:

1. The battery life of both the camera and audio recorder is fairly miserable. Worse, swapping the batteries is slow work, because the recorder blocks the camera’s battery door and I have to remove the recorder’s battery pack to get at the Allen key needed to unscrew the recorder from the camera. It feels like one battery or the other is always about to bring proceedings to a halt.
2. The rear display is dim and tiny, and so tricky to compose and focus on. On the other hand, I had wanted to avoid the bulk, faff, and cost of an external monitor, which might additionally require a cage of some sort.

I’m starting to rethink 2, if it would perhaps solve 1 at the same time. For example, many monitors use Sony L-series batteries. Maybe I can run the camera and recorder off the monitor battery?

For example, SmallHD sells a “Panasonic DMWBLF19 Pack” that looks interesting:

https://smallhd.com/products/focus5-dmwblf19

But I’m not sure the SmallHD Focus monitor (with 1280 × 720 pixels) is good enough for focusing 4K, or whether it even accepts a 4K signal over HDMI. All very confusing.

There’s a way to power the recorder with L-series batteries (that is, Sony NP-F series batteries), but I think it would interfere with the lens in my set-up. Seems to be designed for an audio bag:

https://www.bhphotovideo.com/c/product/1333782-REG/sound_devices_mx_lmount_battery_sled_holds_2.html

There’s also a way to power the MixPre-3 with a Hirose connector from an external battery, but I don’t know if that could also power the camera:

https://www.bhphotovideo.com/c/product/1552856-REG/sound_devices_mx_hirose_hirose_dc_input_sled.html

And Hirose stuff starts to cost real money.

It might help that the fluid head has an accessory for mounting 1/4″-20 accessories weighing up to 1.5 kg / 3.3 lb.

https://www.bhphotovideo.com/c/product/1068902-REG/miller_2092_air_accessory_mounting_block.html

Maybe that could avoid a cage?

Suggestions?