People hate on iPhones a lot but damn do they make this easy. Plug into computer, click “make encrypted image backup.” Wipe phone and set up as new.
Go to other place and use phone as normal. Take all data that’s needed once you’re back at home and upload to encrypted online storage. Wipe phone before traveling back.
Plug phone into computer at home. Click on “make phone the same as it was before I left.” Phone is now the same as it was before you wiped it the first time.