Officially, the adverb 'markably' derived from 'markable' appears not to exist. At least all classical dictionaries (OED, OALD, CALD, LALD, etc. even WordNet v3.1) have no entry.
Theoretically, deriving 'markably' would be allowed. Hence, I want to know on a scale from 0 (not awkward at all) to 10 (super awkward) how awkward it sounds to use '...has been markably exhausting to her'
Which alternative expressions would you suggest in case that you recommend against using 'markably exhausting'?
Thank you for any valuable input.