Well, it’s just “all Royal records” is so very wide. Do you mean all the records of expenditure at any Royal residence? Electricity costs, food bills, cleaning products, refurbishments? What about staffing? Who was rostered on to clean, to garden, to cook, to provide security? Every email, letter, or other type of correspondence that they send or receive? What about their medical records, or children's school records?
Because if that is what you mean, you’ll have to spend public money storing it all (storage, whether of hard or soft copies is very expensive!) plus you need to pay people to read and to index it all, because there is absolutely no point in storing data on that scale unless it’s actually searchable in future. Even if you use AI to do that, it’s a huge cost and it would obviously need to be checked and have controls built in.
You’ll need to deal with all the other privacy rights you are trampling over in storing all that data (for example, details of staff who are working at any given time and what they are paid etc) and either get every single one of their explicit agreement to this (as required by GDPR) or if they don’t agree, paying someone to go through every single record and redact all personal data from it. You’ll have to work out safeguards so that sensitive personal data about the Royal Family members themselves in all this (their medical records, for example) is stored more securely than everything else so it can’t inadvertently be accessed by anyone.
And if you decide you want less than this, you’ll have to pay someone to sift through and identify what is worth storing, and what can be destroyed. Which is what I understand happens currently with the Royal Archives - although its scope is fairly limited compared to what you have in mind.
So to achieve what you want, you’d be looking at a very large outlay of public money every year just to keep a whole load of past information. On what basis? That some future person may at some future stage want to mount a fishing expedition into it? On a cost/benefit analysis, is that really a good or even a reasonable use of public funds?
We don’t do that Government, who actually has the power to impact the lives and livelihoods of residents in the UK.