Browser Settings (pinned tabs & themes) do not save when window is closed & reopened

Heya - This issue has being going on for quite some time. I have four pinned tabs (two of which I no longer use, ever) and often change up the visual theme of my browser as well. However, when I change these (unpin the tabs & change the theme to how I want it to be), when I open Firefox again after, it restores my old pinned tabs & old theme I don't want. I have tried playing with the sync settings but to no avail. On opening Firefox, when it asks me what account I want to use (I just have the one) it does visually still use the last saved theme from my previous session, but on logging in it changes back to the old theme (and old pinned tabs). Thank you so much in advance & let me know if you need more info