Tails on a usb on a personal device only. Never do anything in person. Redact all personal information for all people yourself included. Use a pdf to image embedded pdf conversion tool to hide all possible pdf metadata. Remove all image metadata. Never tell anyone any traceable information this includes names, locations, times, contacts, you voice, anything that can in any way be identified as unique to u.
Do not raise suspicion quit within a short period of disclosure of information, speak out about issurs, etc. Use simplex chat or pgp encrypted email with a new randomly generated email address not linked to personal info (phone number, existing email etc). Do this all via tor on ur tails install.
Data exfiltration is difficult and can be linked/traced depending on threat model (boing will have extreme capacity and can be considered as dangerouse as a government actor). If u can take the device home and their is no device opened detection in BIOS then extract drive plug into personal device thats booted with tails and copy files from drive to tails (avoids any logging of files being copied or what fikes).
If files are on a secure server then exfil will be traceable. U can avoid this by taking pictures of screen with an oldschoop dslr (be carfull of information leakage (the monitor reflections etc).
If u are to testify and therefore need to disclose your real identity then u could theoreticly livestream ur entire life untill the point of testifying at which point u state clearly for the record u are not suicidal that u fear for you life and hope to hell thwy dont suicide u out of spite. Also if ur in the states carry a firearm and learn how to use it effectively.
Also deadmans switch which publicly dumps info. Files, audio/video from ur phone streamed to a remote server (in an internal durastinction they cant get to easily or quickly)
Idk tho just some thoughts