Both Taipa and Cotai contain the character 氹/凼 in their names, with some saying that 凼 is the simplified version of 氹. However, I’ve seen 氹 being used in simplified scripts as well. So, which character is the correct simplified name of Taipa and Cotai
There are no "Simplified" and "Traditional" versions of this character.
The local character used in Macao,「氹」, is the modern version; in older times, it was written as「凼」and「窞」. In the digital age, due to Mainland China initially lacking support for the character「氹」, various publications substituted the character「氹」with the character「凼」instead.
The modern way to write it is「氹」.「凼」was used in the past, when the Mainland didn't encode the character in their digital standards.
the info provided by wiki is, very doubtful.
the character 氹 (u+6c39) was used in 廣東通志 卷五十一
this book was "composed" in 1730 (雍正八年). isn't it old enough to refute the claim of modern version (現代字）, or variant (異體字)
further, the preface of the book "經詞衍釋" mentioned:
the preface was written in 1873.
i would say that 氹 was a cantonese character (粵字), with a long history; that most ordinary rime books, dictionaries did not contain it.
Let's start from the geography and history of Macau first. Taipa is 氹仔 and Coloane is 路環. They were both islands. The reclamation between Coloane and Taipa picked their initials and got its name Cotai (路氹).
氹 is a pit or a pool of water in Cantonese. It is a local form of character 潭. There is a hill on Taipa named 大潭山. Actually 氹仔 is alternative form of 潭仔. There are many names of this island but the people of Macao finally settles it with 氹仔.
氹 is Cantonese only character and early Chinese computing standard GB2312-80 ignores this character. When addressing to this ignorant, some publications in China (PRC) use 凼 instead. 凼 is in the list of GB2312-80.
凼 is not a simplified form of 氹. It is just an early computer problem in China.
For your information, 路環 is a short form of 過路灣. People of Hong Kong and Macau pronounce 灣 as 環 in some place names. Coloane comes from 過路灣 actually. 過路灣 is an old name of the island and no longer in use.