I can't really say that "buying" some dashboard as compared to rolling your own makes all that much sense.
As pointed out, while some of those dashboards might look "really" cool, at the end of the day, YOU the developer still have to build the data queries and build code to total up the summary data you wish to display. In other words, the dashboard only looks cool, but you the developer still have to do all the heavy lifting, and write all of the data warehousing or summary code.
.In other words the fancy looking part is actually NOT where all the work is involved.
I mean, there are boatloads of REALLY nice and free controls. such as gauge.js. In fact, I liked this control so much, that I turned it into a "user control" in which I now can just drop in the control onto a web page.
The gauge control thus looks like this:
Now, say applying a "dark mode" to above, and you have the makings of a cool dashboard. So, just like you see boatloads of "fancy" templates you can buy for laying out a website, the same really applies to a dashboard.
However, at the end of the day, such dashboards are disappointing, since YOU THE developer still has to go and write all the code and summary data. I suppose if you purchased a particular shopping cart application, and the dashboard is specific tailored to that particular database, then such a purchase might make sense.
However, a fancy looking web template, or a fancy looking dashboard template?
It is JUST THAT - a fancy template, and YOU the developer still has to write all the code, all the SQL and all the bits and parts that total's up the data you want to display on such a dashboard. In other words you don't get the code with such dashboards that does all the REAL work of totaling up your data, and summarizing your data.
You need to sit down, and write out (whiteboard) what information you plan to display into that dashboard. In other words, the dashboard is a display page, but NOT a "system" that will automatic summarize your existing data. Unless you done all the work and code and data queries to summarize the data you want, then the dashboard is of little use here.
A cute looking web page is just that - a cute looking web page. It is NOT the code, not the hard work, not the code that produced the summary data in the first place. So, some fancy UI is just that, a fancy UI and has NO RELATION to that of the code behind required to drive such a web page.
In other words, this comes down to taste and style - but NOT something that will do all the real work for you. As a result, I not all that sure I would purchase a dash board, since then you STILL left with having to do all the work. I not actually sure that I should have to explain the above, since from day one in our industry we have groups of people that equate fancy looking pages with that of having fancy code to drive such a page. This of course I accept (that a cool looking UI most certainly DOES give a great impression of the software behind, but they are in fact not related). While everyone accepts that cool looking UI = great code, we developers of course don't accept this view - that is a "user" type of view in this context.
Joel on Software calls the above concept the "Iceberg" principal. In other words, users equate a fancy UI with great code, but great code has rather little to do with a fancy UI. You can read this article about this UI effect on users here: https://www.joelonsoftware.com/2002/02/13/the-iceberg-secret-revealed/
In other words, this comes down to one buying a page with a cute nice looking layout, since the developers you have don't have the ability to layout a great looking page. However, the fact of not having a great looking UI is NOT a reflection of the developer's coding ability.
I cannot stress that making a great looking page vs that of code to total up data, and provide summary data from the database?
They are 2 VERY different goals here.
Such dashboards don't do the code work, they only provide the fancy controls and layout. I would look at a few dashboards, and then roll your own. As noted in the other post here, most of these dashboards are often based on open source controls anyway....