Can I use
?

XHTML served as application/xhtml+xml

- LS

A strict form of HTML, and allows embedding of other XML languages

Chrome

  1. 4 - 107: Supported
  2. 108: Supported
  3. 109 - 111: Supported

Edge

  1. 12 - 106: Supported
  2. 107: Supported

Safari

  1. 3.1 - 16.0: Supported
  2. 16.1: Supported
  3. 16.2 - TP: Supported

Firefox

  1. 2 - 106: Supported
  2. 107: Supported
  3. 108 - 109: Supported

Opera

  1. 9 - 91: Supported
  2. 92: Supported

IE

  1. 5.5 - 8: Not supported
  2. 9 - 10: Supported
  3. 11: Supported

Chrome for Android

  1. 107: Supported

Safari on iOS

  1. 3.2 - 16.0: Supported
  2. 16.1: Supported

Samsung Internet

  1. 4 - 18.0: Supported
  2. 19.0: Supported

Opera Mini

  1. all: Supported

Opera Mobile

  1. 10 - 12.1: Supported
  2. 72: Supported

UC Browser for Android

  1. 13.4: Supported

Android Browser

  1. 2.1 - 4.4.4: Supported
  2. 107: Supported

Firefox for Android

  1. 106: Supported

QQ Browser

  1. 13.1: Supported

Baidu Browser

  1. 13.18: Supported

KaiOS Browser

  1. 2.5: Supported

The XHTML syntax is very close to HTML, and thus is almost always (incorrectly) served as text/html on the web.

Resources:
Information on XHTML5
Wikipedia
Sub-features:
XHTML+SMIL animation