Inertia is not a force.
There are only forces that are related to the natural inertia of a solid body or fluid.
Copied from
https://en.wikipedia.org/wiki/Inertia
"In common usage, the term "inertia" may refer to an object's "amount of resistance to change in velocity" (which is quantified by its mass), or sometimes to its
momentum, depending on the context. The term "inertia" is more properly understood as shorthand for "the principle of inertia" as described by Newton in his
First Law of Motion: an object not subject to any net external force moves at a constant velocity. Thus, an object will continue moving at its current
velocity until some force causes its speed or direction to change."
"Another form of inertia is rotational inertia (→
moment of inertia), the property that a rotating rigid body maintains its state of uniform
rotational motion. Its
angular momentum is unchanged, unless an external
torque is applied; this is also called conservation of angular momentum."