SeoToolkit beta 2 for Umbraco 15 is now out: https://github.com/patrickdemooij9/SeoToolkit.Umbraco/releases/tag/4.0.0-beta2. Also, if you would like to help me figure out the future of SeoToolkit and what features to prioritize, please fill in this form that I have created: https://form.jotform.com/250704498268062. Thank you!