Welcome to the community and thanks for posting!
The SharpTools Android App (Tasker plugins and widgets) has a bit of a legacy, so I can definitely understand the confusion there! As you noted, the SharpTools.io dashboards and Rule Engine can be accessed from any modern web browser.
Beyond just using a normal web browser like Chrome or Safari, a common approach for phones is to use the Add to Homescreen approach:
Many people with dedicated Android tablets (including Fire Tablets) really like an app called Fully Kiosk Browser. SimplySmart123 has a great video on setting up Fully Kiosk Browser:
In fact, SimplySmart123 has a number of great videos about SharpTools. Here’s another video which talks about SharpTools at a high level:
You’ve already found the community which is a great source of information and a great place to ask questions!
In addition to the community, take a look at our Help site which has a variety of articles and documentation:
Help Site: Documentation and Articles