Hey there. Gald you enjoyed it. One strategy would be to do your reading, tagging and situations in Zotero or, my preferred reading app as of late “Highlights” (https://highlightsapp.net/). A combination of the two, Highlights and Devonthink works well. Rather than exporting OPML, with Highlights you can export to markdown. You can then export the markdown, import it into Tinderbox, run an explode and apply a stamp to parse the markdown into attributes (@mwra helped me with the stamp yesterday), see Extract text from the following standard format - #8 by satikusala.
Maybe I need to do a video on this flow.