@Srinivas, apologize for the late response,
1. I have not logged medium! Actually, I don't have experience with Logi Analytics. If we compare Quicksight vs the tools I used in the article - (1) customization, (2) refresh frequency, (3) interactivity, (4) secruity, (5) scalability.
(1) you can add custom colors, there are standard graph types + maps + sankey + world cloud - https://docs.aws.amazon.com/quicksight/latest/user/working-with-visual-types.html;
(2) Quicksight enterprise allows setting an hourly refresh schedule not live connection - https://docs.aws.amazon.com/quicksight/latest/user/refreshing-imported-data.html;
(3) you can add drill-down to graphs - https://docs.aws.amazon.com/quicksight/latest/user/adding-drill-downs.html;
(4) you can cann row-level security - https://docs.aws.amazon.com/quicksight/latest/user/restrict-access-to-a-data-set-using-row-level-security.html;
(5) with enterprise edition you can add 250 million (250,000,000) rows or 500 GB for each dataset - https://docs.aws.amazon.com/quicksight/latest/user/data-source-limits.html. As for the performance, I cannot comment much on the issues observed with the performance as I have not went too deep.
2. In general, the implementation of embedded dashboards with open-source solutions I reviewd is relative actually easy as you just add a snippet of code to your webpage - well, some manipulation with the code is required because if you don't do it and someone access the page editor, they could just extract the dashboard url and then, open the dashboard in a webpage wo a need to log to your application. The question, however, is the functionality of the tool and the level of secruity you require. For example, if you embed Power BI dashboards while being on a Power BI pro license, in order to see the dashobard, a person would have to authenticate to Power BI. So, if you add it to your site/application which already requires a login, you will have two logins.
We used Google Data Studio and faced the issue I decscribed above where if a dashboard is 'open to the web', a person could open the dashboard from your application in his browser and then, just use it wo the application.
If you go for a licensed product, it might be easier and it will have a wider range of features than open-source tools. I need to say that I have not reviewed the Metabase enterprise or Redash enterprise, so I cannot comment on their commercial product. I would expect that commercial providers offer a more secure handling of the embedded dashboards.