pei also works well and is dirt cheap for self adhesive sheets.

BUT !
befoere doing anything expensive you need to play with the slicer settings.
You've actually got thr best start - a print surface things stick well too.
So all you really need to do is to speed up the first layer print speed and adjust the z-axis offset, until you have settings where the print sticks, but also releases.

Having a print surface things stick well to is a great place to start.

So before spending a lot of money on a - probably - not needed upgrade, tune the slicer for the surface you have.
A really sticky surface is actually an advantage as it means you can print your first layer pretty fast.

And a combination of speed and nozzle gap will most likely sort the problem out.