I just made a raindrop.io as well and imported my bookmarks over there. I'll probably save to both pinboard and raindrop: https://raindrop.io/kit12123/import-29085336

One thing about the import is my private bookmarks and public bookmarks all imported into the same collection, and collections are what can be shared. I tend to keep things I've marked as to read later private but there's also a few hundred of those bookmarks so I'm not going to go back and separate into multiple collections because that would be time consuming