I’ve never looked for a BBEdit solution for editing delimited files and will be curious to see the solutions people here suggest.
For editing CSV files I recommend DB-Text, an app from Tension Software which is available in the Mac App Store ($9.99). I use DB-Text to maintain a tab-delimited, Russian-English dictionary file which is now 4 columns by 12225 rows. DB-Text loads my file instantly, has good import/export features, sorts by column, and remembers the last used column widths. When you search the files, it shows only the rows that match the search term. The software developer has responded to my questions and suggestions and has recently issued a maintenance update.