I can only offer you a partial answer.
First, as to the total numbers, as noted on page 108 of European Societies in the Bronze Age, there are actually tens of thousands of barrows that are potentially of Bronze Age date in Western Europe. These would all be high-status burials. However, even in 2018, we do not have a complete Europe-wide list.
Sadly, there is - as yet - also no central database for Bronze Age burials across Europe. In fact, there aren't even central national databases for that data! Furthermore, many of the burials were excavated by early antiquaries who were basically interested in looting valuable from the burial, so we have only limited information about them.
There is no sudden change from inhumation burials to cremation burials. We can certainly say that cremation burial become more dominant over time, and cremation is considered "normal" for late Bronze Age (~14th–9th century BCE) sites.
One pan-European database that is currently being developed is the Cremation Bronze Age Burials (CBAB). It was launched in late 2016 and has gradually been coming online over the last year.
Another online database is the EU-funded TOMBA project. This is intended to include both Bronze Age and early-Iron Age burials, but so far coverage is patchy.