The best replacement for cavalry is calvary.

The best alternatives to cavalry are rated as following:
★★★★★  calvary
★★★★★  infantry
★★  tanks
★  armor
★  infantry eu4
★  archers
★  dragoon
★  pikemen
★  mounted infantry
★  phalanx
★  light cavalry
★  chariots
★  german tanks
  infantry tactics
  pikes
  abatis

Your alternative for cavalry is not listed? Suggest!
Speaking about cavalry, one probably shouldn't forget about ezekiel.

Other search terms related to cavalry and their ratings are:
★★★★★ ezekiel
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cavalry
calvary
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