An LED isn't a resistor, and won't behave linearly the way you're expecting it to - your mental model is flawed and OhmsOhm's Law doesn't apply to LEDs.
The Voltage vs Current graph for a resistor looks something like this - the slope is controlled by the resistor's value, but (but this graph has no scale, so can be used for all resistor values).
The fact that this graph is a straight line is what permits the application of Ohm's Law, emphasis mine:
Ohm's law states that the electric current through a conductor between two points is directly proportional to the voltage across the two points
An LED (Light Emitting Diode) can be conceptualised just like a diode - hypothetically, zero current will flow through it in one direction (i.e: the voltage drop is infinite), and a fixed voltage drop will present in the other direction. It is of course more complicated than that, but let's stick with the basic / perfect model for now.
If you have a diode with a known forward voltage drop (V, Vf) of = 2.1v, you'll get a Voltage vs Current graph looks something like below... (ignoring thevarious realities of life)
The fact that this line is bent, means that Ohm's Law does not apply, and you cannot directly model a diode as a resistor. It's just not possible.
This is also why a current limiting resistor is so important - once you reach the threshold voltage, the current through an LED / Diode will rapidly increase, possibly destroying the part.
LEDs and Diodes don't have a "resistance value", because they aren't resistors.
Would you have a source to read up more on the relationship between diodes and their relationship with current/volt and resistance? I've been reading introductory electronics books and they all gloss over it.
With regards to resistance - as above, it's not that they "gloss over it" so much as that isn't a thing / doesn't make sense.
If you're interested in reading into this further, then you can approximate a diode / LED using the Lumped-Elemenet Model.
Transistor provided a link in the comments, 'Resistance' of an LED, which helps to clarify this a little. Because a part of the graph is straight-ish, you can model it as a resistor... and because there is an apparent voltage offset away from zero, you can model that as a voltage source. However, this is an approximation, and the single LED shown in Transistor's article has two potential solutions depending on which area you're interested in (with more if you're interested elsewhere).
