Edit metadata - Alt/<accellerator keys works for me> there are some ambiguities eg Alt/g for Generate Cover and Tags
GUI based And and Or see - Alter Tag Browser (bottom of left panel)->Search type when... Select All is an AND Select any is an OR
Add books with out tags - not sure that you can, suggest check Mark books as they're added, then Show marked books, select all (ctrl/a), check Remove all tags in Bulk Metadata edit.
I use a third way - a custom column with a defined set of values - that combines my notion of read status - unread, reading, read all, read a bit, reference with a my notion of rating - read all +++++ for a really good (couldn't put it down) book, thru to read a bit ----- for a diabolical book
BR
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