And, a bit of history:
Filibuster first limited in 1917 with 66 votes...by Democrats
Filibuster further limited in 1975 with 60 votes...by Democrats.
Filibuster further limited (for convenient votes) in 2013 with 51 votes...by Democrats.
Source: https://www.senate.gov/artandhistory/history/common/briefing/Filibuster_Cloture.htm
so... it’s only nuclear when Republicans do it?