How to make a usb bluetooth adapter work on linux instead of internal bluetooth?

Have a mini pc with AX210 inside (intel chip that does wifi and bluetooth) but the range on the bluetooth is bad, so I bought a usb bluetooth adapter. It has a realtek chip in it. I am quite new to linux, but I took a gamble that the linux kernel has the firmware for the realtek chip in it (even though product page from store says windows only).

I’m trying to figure out how to get my system to use the bluetooth usb adapter. I’ve found the MAC address of it by doing

dan@archlinux ~]$ bluetoothctl list
Controller 8C:68:8B:A0:80:4C archlinux #1 [default]
Controller A0:02:A5:FF:9B:27 archlinux  
[dan@archlinux ~]$

Doing lsusb:

[dan@archlinux ~]$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 25a7:fa67 Areson Technology Corp 2.4G Receiver
Bus 001 Device 005: ID 8087:0032 Intel Corp. AX210 Bluetooth
Bus 001 Device 006: ID 0573:1573 Zoran Co. Personal Media Division (Nogatech) USB Audio and HID
Bus 001 Device 015: ID 145f:02c9 Trust Trust Keyboard
**Bus 001 Device 023: ID 0bda:a728 Realtek Semiconductor Corp. Bluetooth 5.4 Radio**
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
[dan@archlinux ~]$

I also tried rfkill list:

[dan@archlinux ~]$ rfkill list
1: hci1: Bluetooth
Soft blocked: no
Hard blocked: no
2: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
19: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
[dan@archlinux ~]$

but if I use rfkill to block the AX210 bluetooth, then my system just has no bluetooth at all.

And I made it the default one by doing bluetoothctl select 8C:68:8B:A0:80:4C. This is the mac addy of the usb adapter. But I can’t for the life of me get it to work. I can only connect to headphones etc via bluetooth using the internal intel AX210 controller. Is there a way to sort this? Any help much appreciated