That may be too big of a card, the Bugs 2/3 for example lists 32G max. Do you STOP the video (long press on camera button) before shutting down/removing the battery? That should then save the info to the card.
The only 'plumbers tape' I'm familiar with is Teflon tape, which provides a slick surface on threaded pipe joints. It helps lub the connection, making the threading and disassembly easier.
Just to make sure, have you ever actually tested a battery fresh off the charger with a meter? Maybe you got a bum charger. Those LiHVs should read ~4.35V.
Might be worth a peek. Good reviews.
https://www.banggood.com/Radiolink-Mini-PIX-F4-Flight-Controller-MPU6500-w-TS100-M8N-GPS-UBX-M8030-For-RC-Drone-FPV-Racing-p-1240423.html?rmmds=search&cur_warehouse=CN
I was gifted this exact review model. This was his pic.
I had some major problems trying to get it airborne. Finally I carefully re-read the manual.
I also had major problems trying to bind the RX after the TX/quad updates. Turns out what I thought was the bind plug was actually just...