Lots of people plugging their low sensitivity planars into speaker amps using banana to xlr adapters (any cable maker will be able to make one of these for you). Just gotta be extra careful with the volume as you don't want to blow up your headphones.

https://soundnews.net/headphones/full-size/the-ultimate-hifiman-susvara-review/

this guy recommends driving the Susvara with a speaker amplifier and gives some tips for doing so safely.