Support for Apple Pencil is not universal. Whilst the Apple Pencil uses Bluetooth, the limitation has no bearing at all upon Bluetooth itself; the limitation is in fact special screen hardware that must be incorporated within the iPad, with which the Pencil electronically interacts.
Here is the full compatibility list for Apple Pencil and iPad; the very old iPad mini2 does not feature Pencil support:
Apple Pencil (2nd generation)
You can use Apple Pencil (2nd generation) with these iPad models:
- iPad Air (4th generation)
- iPad Pro 12.9-inch (3rd generation) and later
- iPad Pro 11-inch (1st generation) and later
Apple Pencil (1st generation)
You can use Apple Pencil (1st generation) with these iPad models:
- iPad (8th generation)
- iPad mini (5th generation)
- iPad (7th generation)
- iPad (6th generation)
- iPad Air (3rd generation)
- iPad Pro 12.9-inch (1st or 2nd generation)
- iPad Pro 10.5-inch
- iPad Pro 9.7-inch
Not sure which iPad you have? Identify your iPad model.
As for a third-party Bluetooth stylus, if available, these all require explicit support by Apps. Bluetooth Stylus do not have system-level integration and support. The Adonit Pixel line of Bluetooth Stylus used to have limited support by some third-party drawing Apps - but the Adonit Pixel has not been available for some time.
This leaves a “simple” Capacitive Stylus - which, other than providing more accurate tip placement on the screen, provides no more capability than your fingertip.
Given that the iPad mini2 is rapidly ageing - and has reached the end-of-the-line for major system updates - you might be better advised to consider replacement of the iPad with a more recent model that supports iPadOS14 and Apple Pencil.
iPad mini2 can only be updated to iOS 12.4.9. Apple ended major update support for iPad mini2 in September 2019. The iPad mini2 cannot be updated to iPadOS 13 (or any later major versions of iPadOS) as the internal hardware does not meet the minimum technical requirements (RAM and CPU) for new versions of iOS/iPadOS.
Some App developers have dropped support for iOS versions preceding iOS 13.x for technical reasons (often because APIs or software libraries upon which they rely have been updated in the new version of iPadOS, making their App incompatible with earlier versions).
Whilst many App titles remain compatible with your iPad mini2, if you want or need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model that supports iPadOS14.
Sorry, I appreciate that this may not be what you were hoping to learn.
I hope this information provides helpful clarity as to your available options - and the limitations of your current iPad mini2.