Here are some notes before I forget. More research required.
- read your message about site data
- unchecked "delete cookies and site data on close"
- launched game
- Game started after gate1, but with 0 souls
- got 4 (more) souls
- quit and closed browser
- restarted
- state and (4) souls were correct.
- firefox reports 7 cookies from itch.io
- firefox reports storage only from the 3 sites I always have
- closed and reopened browser.
- told browser to selectively delete cookies from itch.io
- game still started in correct location with 4 souls.
- deleted itch.io exception and checked the "delete on close" box
- restarted browser.
- starts after gate1 with zero souls.