OP in the kindest way, please try to stop fretting. "Taken advantage of" is simply not a relevant concept here.
You put the house on the market at a particular price. IIRC, your buyers have offered you that price. You simply can't ask fairer than that!
Your price was based on the highest estimate from a number of estate agents. You say two of them gave the same high figure. All of them will have much, much more experience of the local market than you. Naturally, they aim to get the highest price for you that can reasonably be expected. The fact that all the offers they received except one were below your asking price shows that it would have been unreasonable of them to suggest a higher selling price. That's not "taking advantage of you", either.
As others have said, you don't have to sell. But it's an uncertain market and in many places a falling one. Inflation, rising energy prices etc are likely to make people more cautious; many will have less to spend on all the costs of moving or on bigger mortgages.
Remember, not all buyers like or value the same things. If it matters, an open plan kitchen with modern appliances would de-value a house for me. I'd much rather buy a house with original proportions - and choose my own kitchen fitments.
As many others have said, a house is only worth what someone is prepared to pay for it. Did you get any offers above asking price? If not, then I think that gives you a pretty good indication of the current house value.
For Zoopla estimates, this is from a property trade website:
"Your house might be worth a lot more than Zoopla estimate it is. Or your house may be worth a lot less than Zoopla estimate it is. If you want to sell your house it’s best not to get too excited, or be too disappointed, by Zoopla’s estimate." (source below)
This article explains how Zoopla estimates work - and how many factors that Zoopla does not measure can also affect valuation :
www.propertyinvestmentsuk.co.uk/zoopla-valuations/