how to use servodrive with resolver

You can use resolvers directly (7i49, for example, with a torque-mode or (tacho) velocity mode servo drive.)

Or you can use a drive that uses the resolvers and outputs quadrature signals to the controller.

The 7i49 expects to be the excitation source for the resolver, though. So it isn't really possible for both the drive and controller (LinuxCNC) to share the resolver.

I have two machines using resolver servos and the 7i49. But both of them are using Mesa 8i20 servo drives, so all the loops are in LinuxCNC.

A really neat solution is the STMBL drive, that can drive the servos directly, using resolver feedback, and the control signal is floating-point positions on the Mesa smart-serial protocol. But currently there is a supply problem with a critical component of the the STMBL so it is not necessarily an available solution.

I am using one of the Moog motors like your 5A on my milling machine Z axis, so it can definitely be made to work.

The 8i20 is just a dumb drive. It has no feedback built in and almost no onboard processing. You send it a current demand and rotor angle down the smart-serial line and it generates a suitable phase angle in the motor magnetic field.

To convert the resolver feedback to rotor angle I use a Mesa 7i49.

The 7i49 can also generate analogue output for a servo drive, but that is not useful when using an 8i20.