You got to take many pictures with many different angles. If you use flashes on tripod it will be your problem. You must change positions of two tripods with flashes every 3-5 minutes. It is a hard workflow.
Only powerfull mobile flashlight will help you. In absolutely dark cave I using oncamera ring flashlight. Same device with differnent names:
Grifon WISTRO AR-400
Godox Witstro AR400
Flashpoint RF-400 Ring Li-On 400ws Ringflash