Is Spending N16M On A 3-Year Ph.D In The UK Worth It?

Hello everyone - I'm not quite sure whether this is the right section to post this.

Anyways, I currently hold a Master's degree and I also recently gained admission into a PhD program in a UK university but with no funding from the school and the estimated total cost of the tuition and living expenses amount to about #16 million for the 3 years.

So, I decided to come seek the opinion of folks here with better experience if it really worth spending this amount in the long run or should I rather invest this amount?

Thank you in advance!