I think that these four characters are being used:

Notice anything off about the last one? It was added in Unicode 13 in a new block. This means very much reduced font support, and if absent, it generally means the use of a fallback font, which is very likely to mean a wider glyph, which means that the right edge of your box is displaced and probably the wrong thickness, and in some environments (though no proper terminals) anything following it will be offset too.

Sample with line-height 1 (which will look better in some fonts and awful in others):

  โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–
  โ–ŽUsing this new technique๐Ÿฎ‡
  โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”

Sample with the default line-height (which actually might not match what youโ€™ll get in a terminal, which is probably between the two; this will probably look worse than in the terminal):

  โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–โ–
  โ–ŽUsing this new technique๐Ÿฎ‡
  โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”โ–”

In environments that use an increased line-height (not unknown in terminals, and very common outside terminals), this will mean unbalanced gaps too, compared with the traditional technique which will either be nicely joined or have balanced gaps:

  โ”Œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”  โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”“
  โ”‚ Traditional technique โ”‚  โ”ƒ Traditional technique โ”ƒ
  โ””โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”˜  โ”—โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”›

  โ”Œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”  โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”“
  โ”‚ Traditional technique โ”‚  โ”ƒ Traditional technique โ”ƒ
  โ””โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”˜  โ”—โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”โ”›