The Unicode page about Unicode Regular Expressions (UTS #18), dated February 8, 2022, has never been updated since then.

https://www.unicode.org/reports/tr18/

The four new Unicode properties: IDS_Unary_Operator, ID_Compat_Math_Start, ID_Compat_Math_Continue, and NFKC_Simple_Casefold, introduced in Unicode 15.1, are only listed later in the Proposed Update page, dated May 11, 2023.

https://www.unicode.org/reports/tr18/proposed.html

It is unclear whether this document is a reference for third parties, but not having it kept up-to-date would explain why all implementations of regular expressions in JavaScript in navigators such as Safari or Firefox, or in the Electron framework based on Chromium, or even in the NPM module regexpu-core, appear to have no support for those four new properties: for instance, while the regex \p{IDS_Binary_Operator}/u is just fine, \p{IDS_Unary_Operator}/u triggers an "Invalid regular expression" error...