Both objective and subjective theories of value are incomplete. Both theories like the Labour Theory of Value and Marginalism hold grains of truth, but do not paint the whole picture. Value is an objective measurement of subjective conscious experience. What we value is positive conscious experiences which we can only experience by being alive and spending time experiencing them. Therefore, the proper unit of measure of value is time.
It costs us time from our limited lifespan to work and do things that are necessary to survive longer and be able to experience happiness. Ultimately time is the limiting resource that constrains us most. Right now, there is more space, mass, and energy in the universe than we can effectively utilize. But time, humans cannot gain more time than they have at any given moment. Every human being at a given moment has the same amount of time to use as anyone else for experiencing things themselves. At the same time, it is free. We all experience time in equal dosages. This allows time to function as a metric of comparison between morally equal subjects.
In this sense, the Labour Theory of Value has a grain of truth. Labour or work is an expenditure of time and energy, and costs us precious moments we could be enjoying doing other things. In this sense, the subjective theory also holds a grain of truth, in that we choose to spend our time in the form of money earned in exchange for things that enable a future of subjectively desirable experiences.
Prices insofar as they are influenced by demand, thus reflect the amount of time we are willing to spend for goods and services that improve our time alive. Prices, insofar as they are influenced by supply, also reflect the amount of time spent by people to create those goods and services. This supply and demand interaction is a combination of the objective and the subjective.