Thank you so much. So, here's my experience.
Importing bookmarks:
The first link opera://settings/importData worked for importing Chrome bookmarks straightaway with no trouble provided if you have already signed in to your Google Chrome account in Opera GX.
Importing passwords:
The second link opera://settings/passwords however, did not work for me until I found another thread that says you have to do an extra step to trigger it. So here's what I did.
I punched in opera:flags#PasswordImport and "Enable" it, then press "Relaunch" when a dialog box pops up. After it relaunched, go to opera:settings/passwords again and there the 3-horizontal-dots symbol on the right of "Saved Passwords" will appear, click and select "Import", then select your .csv file that you've exported from Chrome.
