App wont start "Could not find the default font"

Here is the yaml file

name: xbr-dashboard
version: '0.1'
summary: TBD
description: |
  TBD

grade: devel
confinement: devmode

apps:
  xbr-dashboard:
    command: python3 $SNAP/main.py
    environment:
      LIBGL_DRIVERS_PATH: $SNAP/usr/lib/x86_64-linux-gnu/dri

parts:
  dashboard:
    plugin: python
    source: .
    python-packages:
      - pyside2
    stage-packages:
      - libnss3
      - libxcomposite1
      - libxcursor1
      - libxtst6
      - libxrandr2
      - libasound2
      - libglu1-mesa
      - libgles2-mesa
      - xfonts-base
      - fontconfig-config
  launcher:
    plugin: dump
    source: .
    after:
      - dashboard

and here is the actual error

[28151:28151:0815/072128.636406:FATAL:platform_font_linux.cc(83)] Check failed: InitDefaultFont(). Could not find the default font
#0 0x7f8dcbe0872f <unknown>
#1 0x7f8dcbe23c4c <unknown>
#2 0x7f8dcc7550c0 <unknown>
#3 0x7f8dcc75511e <unknown>
#4 0x7f8dcc74ba91 <unknown>
#5 0x7f8dcb28bfaa <unknown>
#6 0x7f8dcb28c020 <unknown>
#7 0x7f8dca8bf300 QtWebEngineCore::WebContentsAdapter::initialize()
#8 0x7f8dca8c159b QtWebEngineCore::WebContentsAdapter::load()
#9 0x7f8dca8c1cb0 QtWebEngineCore::WebContentsAdapter::load()
#10 0x7f8dd12a333d Sbk_QWebEngineViewFunc_load
#11 0x00000053b9c6 PyEval_EvalFrameEx
#12 0x0000005416ea PyEval_EvalCodeEx
#13 0x0000004ebd23 <unknown>
#14 0x0000005c1797 PyObject_Call
#15 0x0000004fb9ce <unknown>
#16 0x0000005c1797 PyObject_Call
#17 0x000000574999 <unknown>
#18 0x00000057f03c <unknown>
#19 0x0000005c1797 PyObject_Call
#20 0x00000053bba6 PyEval_EvalFrameEx
#21 0x000000540199 <unknown>
#22 0x000000540e4f PyEval_EvalCode
#23 0x00000060c272 <unknown>
#24 0x00000060e71a PyRun_FileExFlags
#25 0x00000060ef0c PyRun_SimpleFileExFlags
#26 0x00000063fb26 Py_Main
#27 0x0000004cfeb1 main
#28 0x7f8ddbaed830 __libc_start_main
#29 0x0000005d6049 _start

Received signal 6
#0 0x7f8dcbe0872f <unknown>
#1 0x7f8dca83a79d <unknown>
#2 0x7f8dcbe08c3e <unknown>
#3 0x7f8ddbea8390 <unknown>
#4 0x7f8ddbb02428 gsignal
#5 0x7f8ddbb0402a abort
#6 0x7f8dcbe071a9 <unknown>
#7 0x7f8dcbe23d9f <unknown>
#8 0x7f8dcc7550c0 <unknown>
#9 0x7f8dcc75511e <unknown>
#10 0x7f8dcc74ba91 <unknown>
#11 0x7f8dcb28bfaa <unknown>
#12 0x7f8dcb28c020 <unknown>
#13 0x7f8dca8bf300 QtWebEngineCore::WebContentsAdapter::initialize()
#14 0x7f8dca8c159b QtWebEngineCore::WebContentsAdapter::load()
#15 0x7f8dca8c1cb0 QtWebEngineCore::WebContentsAdapter::load()
#16 0x7f8dd12a333d Sbk_QWebEngineViewFunc_load
#17 0x00000053b9c6 PyEval_EvalFrameEx
#18 0x0000005416ea PyEval_EvalCodeEx
#19 0x0000004ebd23 <unknown>
#20 0x0000005c1797 PyObject_Call
#21 0x0000004fb9ce <unknown>
#22 0x0000005c1797 PyObject_Call
#23 0x000000574999 <unknown>
#24 0x00000057f03c <unknown>
#25 0x0000005c1797 PyObject_Call
#26 0x00000053bba6 PyEval_EvalFrameEx
#27 0x000000540199 <unknown>
#28 0x000000540e4f PyEval_EvalCode
#29 0x00000060c272 <unknown>
#30 0x00000060e71a PyRun_FileExFlags
#31 0x00000060ef0c PyRun_SimpleFileExFlags
#32 0x00000063fb26 Py_Main
#33 0x0000004cfeb1 main
#34 0x7f8ddbaed830 __libc_start_main
#35 0x0000005d6049 _start
  r8: 00007f8ddbe93770  r9: 00007f8ddc29f700 r10: 0000000000000008 r11: 0000000000000202
 r12: 00007f8dd932f140 r13: 00007fff2e383580 r14: 0000000000000082 r15: 00007f8dd932e1c0
  di: 0000000000006df7  si: 0000000000006df7  bp: 00007fff2e383320  bx: 00007fff2e3839d0
  dx: 0000000000000006  ax: 0000000000000000  cx: 00007f8ddbb02428  sp: 00007fff2e3831e8
  ip: 00007f8ddbb02428 efl: 0000000000000202 cgf: 002b000000000033 erf: 0000000000000000
 trp: 0000000000000000 msk: 0000000000000000 cr2: 0000000000000000
[end of stack trace]
Calling _exit(1). Core file will not be generated.

I cant tell anything about the fonts (though i’D suggest taking a look at the various desktop launchers and copying teh FONT_* variables from there to your environment entry) but in case your snap is planned to ever run on nvidia based systems, you should extend the LIBGL_DRIVERS_PATH variable to also make it find the nvidia driver, see: