With a Voltmeter we are only inferring the "pressure" from the rate of flow of current. It seems to me that we can only measure Voltage if a current is flowing.
There are several ways to measure volts and the simplest practical design is with a moving coil meter. These do, indeed, derive a voltage measurement through a current flow (Any 105 year-old knows that.). This is a necessity for a passive device - the needle isn't going to move without some energy being expended. The fact that such current is drawn from the circuit under test has always been a key parameter in the design of 'voltmeters'. The target is making that current as small as possible. When I first started out, the basic minimum standard for a decent multimeter was one that was 20 Kohm/volt. With a little bit of maths, you can work out the loading on the circuit being measured.
However, there are other ways, but these require some active circuitry.
The modern DMM is one example where the circuitry is still dependent on current flowing through a resistor divider network to scale down the voltage being measured, but the input impedance can be much, much higher, due to the active circuitry involved. The VTVM (Vacuum Tube Volt Meter) was an early candidate for 'as-ideal-as-you-can-get-on-a-work-bench' volt meter, but it, too, had the resistor divider network loading.
Nevertheless, it is possible to measure a voltage without loading the circuit under test. The fundamental method is to have a power supply provide a voltage of
exactly the same magnitude as the circuit under test and measure the voltage on the power supply. The practical means to ensure the voltages are identical is to have a sensitive ammeter joining the two points - and when that shows a zero current, the circuit under test is not being loaded and you can record your measurement.
This is actually doable on your typical workbench for steady DC voltages, if you have a bench supply that can match the voltages being checked ... but it isn't really practical. For AC voltages, it gets complicated.