Gmail side (use 2-Step Verification and generate app password) :

*Because Google stopped supporting “Less Secure Apps” as of May 30th, 2022, seems this is a MUST to config this.

Google Account -> Security -> 2-Step Verification -> Input password as asked -> Turn ON (you could use SMS to get Gmail code to activate 2-Step Verification)
Google Account -> Security -> 2-Step Verification -> App password -> Input password as asked -> Select the app as mail and device... -> e.g. Other(Custom name) -> Input app name e.g. MyApp -> Generate
Copy a 16-character password
Use a 16-character password with Gmail username (xxx@gmail.com) in Liferay side.

Google support link here.

Liferay side: