A mortgage valuation is instructed by a bank.
A bank makes money by lending money.
A bank wants as many people to borrow as possible!
However, they need insurance.
If they don't think the asset is worth the price of the loan they feel they have no way to recoup their money should you not be able to pay.
Houses are being down valued because banks are preparing for a market correction/crash. Banks are giving this guidance to valuers.
Added to the ridiculous post Covid increase this is no surprise.
Yes, people have been talking about a crash for a long time. However, banks and access to lending determines the market and nothing else.
If they are not lending, surely there is no greater indicator that the correction has already started. Temporary market boosting activities such as the stamp duty break included.
Rather than find another valuer, perhaps you should be asking yourself if you're comfortable paying for something above the value that a property professional has deemed it. Not an estate agent 'professional' but one without vested interests.