Admittedly (adverb)
As is acknowledged to be true; by general admission; confessedly.
“Admittedly, vandalism is a bit of problem.”
Admittingly (adverb)
By one’s own admission; admittedly.
Wiktionary
Admittedly (adverb)
used to express a concession or recognition that something is the case
“admittedly, the salary was not wonderful”
Oxford Dictionary