Hi Jeff_M:
An uninstall and reinstall of Firefox from Settings | Apps or Control Panel | Programs | Programs and Features should not delete Firefox profile data such as bookmarks and passwords, but backing up that data before starting is always a good practice just in case something goes wrong.
See the Mozilla support article Troubleshoot and diagnose Firefox problems.
When you reinstall Firefox (Step 4 of that article) this only reinstalls the program files in the installation folder at C:\Program Files\Mozilla Firefox, but “this process will not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location” at C:\Users\yourusername\AppData\Roaming\Mozilla\Firefox\Profiles.
When you refresh Firefox (i.e., restore your Firefox profile to its default state - see Step 5 of that article),"your bookmarks, browsing history, open tabs, windows, passwords, cookies and web form auto-fill information will be saved. However, your extensions and themes will be removed and your preferences will be reset”.
When you create a new Firefox profile (Step 6 of that article) your personal Firefox profile data like bookmarks and passwords will be deleted. If you neglected to back up that data in a safe location before starting (i.e., so you can easily import this data back into your new profile) you may still be able to recover this data from your old Firefox profile.
Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.6218 * Firefox v142.0.0 * Microsoft Defender v4.18.25070.5-1.1.25070.4 * Malwarebytes Premium v5.3.7.209-139.0.5357 * Macrium Reflect Free v8.0.7783 * CCleaner Free Portable v6.39.11548 * HDCleaner Portable 64-Bit v2.091