We know how much the Sovereign Grant is because that is determined by the government each year.
https://www.gov.uk/government/publications/sovereign-grant-act-2011-guidance/sovereign-grant-act-2011-guidance
At the moment it's £86m, which compares with about £4b for the Department of Digital Media Culture and Sport.
Most of the money goes on upkeep for the Royal residences.
https://www.bbc.co.uk/news/explainers-57559653
Of course, the Royal Family have lots of other private sources of income, as well as the more well known ones like the Duchy of Cornwall. I don't suppose any estimates are completely accurate because, unlike places like Sweden or Norway, we don't expect people to record their income publicly. However, I think the Duke of Westminster (mainly property) was wealthier than the Queen and now presumably the King.
The big taxpayer expenditure is on security - the daily expenditure on security officers and the separate expenditure on large events. There are lots of quotes for the cost of security at the Coronation but these aren't finalised yet. However, this is not just security for the Royal Family but also the costs of security for foreign heads of state etc, as well as the general public. The other cost is on preparation, like the procession, on the assumption that we can separate these costs from other parts of their jobs.
Employers have to pay the costs of an additional Bank Holiday but retailers and leisure businesses will recoup more in extra sales. I personally think the cost to employers statistic is unhelpful as it doesn't take account of any extra employee wellbeing from having an extra day off.
As for how much 'work', the Royal Family do, the Palace publishes a list of engagements each day. I believe Princess Anne is always near the top of the annual list of engagements but presumably other less busy members of the Royal Family 'make' more per day in terms of attracting tourists and well wishers etc.
I think the answer to your question, 4plusthehound, is not that we aren't given access to information on the costs of the coronation etc but that it is a complicated answer that needs to include a lot of different costs, most of which are spread across different sectors of the economy and public expenditure.