Thanks for your words. I love hearing about the issues people experience with the product. Had a few more thoughts around what you said:
Search & indexing - You are right, Examine will fail at some point given too much data. It's hard to tell when that happens. Ultimately, Examine is file based and so, limited by the filesystem. Did you know you can soon replace Examine? [Umbraco.Cms.Search](
https://github.com/umbraco/Umbraco.Cms.Search) is currently in beta, but expect to ship soon including support for V17 and V18. It will allow you to plug in Elastic Search, which should be more than capable of carrying that amount of data.
Dynamicly gereated and interactive pages - It seems to me like you are in a scenario, where you need to extend your application rather than force Umbraco CMS into a situation it's not suited for (square peg in round hole kind of scenario). You can add your own tables to the database, create repositories and controllers and handle the data like you would. You can do all of that whilst referencing Umbraco data. There are packages that add "custom data pickers" to Umbraco handling your data. [Contentment](
https://marketplace.umbraco.com/package/umbraco.community.contentment) is one such example with its 'Data Picker'.
a required field is on a non-active tab - Sounds like a [bug report](
https://github.com/umbraco/Umbraco-CMS/issues) waiting to happen?