How to choose tools for web dashboard?

I am working in a small sales company. Started with making relatively easy, small, static reports in Excel, but then it was required to make a lot of highly-customizable and adaptable reports, that are really troublesome to do in Excel. I do a lot of VBA, but that still doesn't meet my needs. Our ERP has no BI solution. Excel can't keep up with amount of data used (millions of lines).

I am only accustomed to JS and HTML and have some experience working with relational databases (MySQL, MariaDB in particular).

Basically, what I need help with is deciding what tools would be appropriate for my needs considering I am not in a rush and would like to develop some skills along the way.

I would like to create a dashboard that would retrieve data from a local DB and process it. I would also need the dashboard to be dynamic - be able to change some inputs and run calculations accordingly. I am interested in packages that are suitable for mathematical analysis. Reports would include both tables and graphs.

I've read about R and Python packages, but still am not sure which one would be the most appropriate.

In the future I guess I would like to distribute it to other colleagues (run it from a server; have different accounts with different access level etc.).

Will highly appreciate any tips!