Debts have to be compared to assets. We can say some of the richest people in the world are really far in debt based on loans they have, but that would paint an incomplete and very distorted picture
There have been on-going conversations around how the very wealthy get around taxes by holding assets that are only taxed on selling them and borrowing money against their value at a very low interest rate. That's similar to what governments do - making loans with each other against their assets, but between their interest rates have been slowly going up and political desires to use debts as a rallying cry, questions have arisen on debts.
Many alternatives have been given to cutting benefits for disabled people, including from some of the ways income has been raised in generations past (with the recent conversation in increasing defence spending, some people have brought up what Keynes proposed back in 1941...). The proposals I'm most fond of tend to be those of less tax benefits, like the government having one rate of pension tax relief, rather than paying wealthier people more.
Do we as a "Government" lend money to other countries?
Yes, governments lend money to other countries, among other places. Loan to be paid are a form of assets that governments have been using to make money for centuries. There are a lot of complaints around some of the loans that've going on for that long...
You can look at UK lending to other governments here: https://www.gov.uk/government/collections/uk-lending-to-national-governments
It has trillions in assets and treasure. Why not sell some of these?
I think they're likely wary of that after what happened with the gold reserves and the controversy still around that so many years on.