No, it’s not like that at all, Jim.
The EU flatly refuses to discuss anything other than the bill, Citizenship rights for EU citizens living in the UK and the Irish Border. Until these things are agreed no other talks can take place. Concentrating solely on the bill for the moment, the UK could agree to pay (say) £30bn with no guarantee that any trade agreement will be concluded in time for out departure or at all. The bill (if one is to be agreed) should form part of the overall negotiations and not be something that must be agreed up front before anything else is discussed.
The fault with this impasse lies principally with the UK for agreeing to such terms of reference before the talks began. There is no justification for the “divorce bill” being settled in isolation. It’s rather like, in a real divorce, one party saying “pay me £500k and only then will we talk about who gets the car, the house and the dogs”. That is not negotiation, it is setting pre-conditions.