A long time ago I purchased music on iTunes, I now wish to access my library via apple music as that is what most modern things are compatible with.
But for apple to allow me to access my library on another of their apps they need me to pay for a subscription service to access the music I've already paid them for? Either I've made a mistake or this is just a vile tactic to claw money out of people?
You do not need to pay for an Apple Music subscription to access your previous purchases. That is an erroneous assumption.
What device are you using for this exactly?
On a Windows PC for instance, follow the steps in the support document linked below.
click here ➜ Redownload music from the iTunes Store on your PC - Apple Support
You don't need to have a subscription to access your iTunes purchases with Apple Music. What are you seeing that makes you believe that.
Why must I pay twice?
