我最近開始讀《Bitter Medicine》，是一位本現代玄幻愛情小說。

"一本" is more appropriate for books.

Mia Tsai，一位台美推想小说女作家，寫了這本小說。

Regarding the use of 台美作家 to refer to a Taiwanese American author,
there are alternative expressions in traditional Chinese that can also be used, such as 台裔美籍作家 or 台灣裔美國作家. I believe that 台美作家 is also a commonly used expression that effectively conveys the author's identity.
I also asked some friends who use simplified Chinese, and they mentioned that 台美作家 is not commonly used in their experience. This could be due to regional differences or language preferences.
Ultimately, the choice of terminology may depend on personal preference and context. XD

我最近開始讀《Bitter Medicine》，是一位本現代玄幻愛情小說。

Mia Tsai，一位台美推想灣裔美國推理小说女作家，寫了這本小說。

書的簡介也說除了寫東西以外，她還喜歡照顧她的蘭花。