The TinyMCE for Umbraco package released a 17.3.4 version that aligns with Umbraco 17.3.4, has some fixes and adds the Block copy/paste feature to TinyMCE RTEs https://github.com/ProWorksCorporation/TinyMCE-Umbraco/releases/tag/release-17.3.4 https://www.nuget.org/packages/TinyMCE.Umbraco/17.3.4