Google Datastudio, the free, convenient and easy-to-use dashboard solution from Google, unfortunately does not offer out-of-the-box support for third-party marketing platforms. So you can either use a Community Connector from different providers or you can program your own Community Connector in Google Apps Script, which in most cases is not that complicated.
Google offers Optimize 360, an enhanced paid version of its A/B testing and website personalization tool that competes directly with Optimizely. Even the free version of Google Optimize has virtually all the features you would expect as a website operator for Conversion Rate Optimization (CRO) and A/B Testing.
There are only few differences between the free Google Tag Manager version and GTM360. This is probably also the reason why this product of the 360 Suite is not sold separately as an independent product, but is only offered in connection with Google Analytics 360 as a free additional service.
GA360, the paid version of Google Analytics offers a number of interesting enhancements and additional features compared to the free Analytics version. This article provides an overview of the differences between the two versions. Basically, Google Analytics 360 targets larger companies with costs of about $135k per year that have a lot of users on their website.