connman-gtk does allow to turn on bluetooth if set to "enabled" but only for a very short while, practically blocks straight away. 
rfkill state goes from UNBLOCKED to SOFT_BLOCKED
~ ❯❯❯ tail -f /var/log/syslog 130
Feb 15 17:08:17 localhost laptop-mode: enabled, not active
Feb 15 17:08:17 localhost rfkill: block set for type bluetooth
Feb 15 17:08:17 localhost laptop-mode: enabled, not active
Feb 15 17:08:17 localhost rfkill: block set for type bluetooth
Feb 15 17:08:18 localhost laptop-mode: enabled, not active
Feb 15 17:08:18 localhost rfkill: block set for type bluetooth
Feb 15 17:08:18 localhost systemd[1]: Reached target Bluetooth.
Feb 15 17:08:18 localhost systemd[1]: Stopped target Bluetooth.
Feb 15 17:08:21 localhost systemd[1]: systemd-rfkill.service: Succeeded.
Feb 15 17:08:24 localhost blueman-mechanism: Exiting
Feb 15 17:08:45 localhost URfkill[1637]: device_changed_cb: tpacpi_bluetooth_sw
Feb 15 17:08:45 localhost URfkill[1637]: killswitch state: KILLSWITCH_STATE_SOFT_BLOCKED new_state: KILLSWITCH_STATE_UNBLOCKED
Feb 15 17:08:45 localhost systemd[1]: Starting Load/Save RF Kill Switch Status...
Feb 15 17:08:45 localhost systemd[1]: Started Load/Save RF Kill Switch Status.
Feb 15 17:08:45 localhost kernel: [ 2209.329466] usb 2-7: new full-speed USB device number 14 using xhci_hcd
Feb 15 17:08:45 localhost kernel: [ 2209.478741] usb 2-7: config 1 interface 1 altsetting 0 endpoint 0x3 has wMaxPacketSize 0, skipping
Feb 15 17:08:45 localhost kernel: [ 2209.478744] usb 2-7: config 1 interface 1 altsetting 0 endpoint 0x83 has wMaxPacketSize 0, skipping
Feb 15 17:08:45 localhost kernel: [ 2209.478749] usb 2-7: New USB device found, idVendor=8087, idProduct=07dc, bcdDevice= 0.01
Feb 15 17:08:45 localhost kernel: [ 2209.478751] usb 2-7: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Feb 15 17:08:45 localhost URfkill[1637]: adding killswitch idx 12 soft 0 hard 0
Feb 15 17:08:45 localhost URfkill[1637]: killswitch state: KILLSWITCH_STATE_UNBLOCKED new_state: KILLSWITCH_STATE_UNBLOCKED
Feb 15 17:08:45 localhost URfkill[1637]: Setting device 12 (BLUETOOTH) to unblock
Feb 15 17:08:45 localhost kernel: [ 2209.494302] Bluetooth: hci0: read Intel version: 370710018002030d00
Feb 15 17:08:45 localhost kernel: [ 2209.494332] bluetooth hci0: firmware: direct-loading firmware intel/ibt-hw-37.7.10-fw-1.80.2.3.d.bseq
Feb 15 17:08:45 localhost kernel: [ 2209.494334] Bluetooth: hci0: Intel Bluetooth firmware file: intel/ibt-hw-37.7.10-fw-1.80.2.3.d.bseq
Feb 15 17:08:45 localhost laptop-mode: enabled, not active
Feb 15 17:08:45 localhost rfkill: block set for type bluetooth
Feb 15 17:08:45 localhost URfkill[1637]: device_changed_cb: tpacpi_bluetooth_sw
Feb 15 17:08:45 localhost URfkill[1637]: killswitch state: KILLSWITCH_STATE_UNBLOCKED new_state: KILLSWITCH_STATE_SOFT_BLOCKED
Feb 15 17:08:45 localhost URfkill[1637]: device_changed_cb: hci0
Feb 15 17:08:45 localhost URfkill[1637]: killswitch state: KILLSWITCH_STATE_SOFT_BLOCKED new_state: KILLSWITCH_STATE_SOFT_BLOCKED
Feb 15 17:08:45 localhost kernel: [ 2209.547978] usb 2-7: USB disconnect, device number 14
Feb 15 17:08:47 localhost kernel: [ 2211.557439] Bluetooth: hci0: command 0xfc8e tx timeout
^C
Uninstalling connman isn't a good idea on E23 as "nm-manager" doesn't open aymore there. 
