Why doesn't this work in a brand new venv? 

sypherwork@sypherwork3080:~/Desktop/work_after_jail/JoinVC$ source AfterJailVoice2/bin/activate
(AfterJailVoice2) sypherwork@sypherwork3080:~/Desktop/work_after_jail/JoinVC$ pip3 install -U pytgcalls[telethon]
Collecting pytgcalls[telethon]
  Using cached pytgcalls-2.1.0-py3-none-any.whl (45 kB)
  Using cached pytgcalls-2.0.0-py3-none-any.whl (45 kB)
  Using cached pytgcalls-1.0.0-py3-none-any.whl (55 kB)
  Using cached pytgcalls-0.0.24-py3-none-any.whl (21 kB)
WARNING: pytgcalls 0.0.24 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.23-py3-none-any.whl (21 kB)
WARNING: pytgcalls 0.0.23 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.22-py3-none-any.whl (21 kB)
WARNING: pytgcalls 0.0.22 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.21-py3-none-any.whl (21 kB)
WARNING: pytgcalls 0.0.21 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.19-py3-none-any.whl (19 kB)
WARNING: pytgcalls 0.0.19 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.18-py3-none-any.whl (19 kB)
WARNING: pytgcalls 0.0.18 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.17-py3-none-any.whl (18 kB)
WARNING: pytgcalls 0.0.17 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.16-py3-none-any.whl (17 kB)
WARNING: pytgcalls 0.0.16 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.15-py3-none-any.whl (17 kB)
WARNING: pytgcalls 0.0.15 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.14-py3-none-any.whl (17 kB)
WARNING: pytgcalls 0.0.14 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.13-py3-none-any.whl (17 kB)
WARNING: pytgcalls 0.0.13 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.12-py3-none-any.whl (17 kB)
WARNING: pytgcalls 0.0.12 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.11-py3-none-any.whl (15 kB)
WARNING: pytgcalls 0.0.11 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.10-py3-none-any.whl (14 kB)
WARNING: pytgcalls 0.0.10 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.9-py3-none-any.whl (14 kB)
WARNING: pytgcalls 0.0.9 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.8-py3-none-any.whl (14 kB)
WARNING: pytgcalls 0.0.8 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.7-py3-none-any.whl (14 kB)
WARNING: pytgcalls 0.0.7 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.6-py3-none-any.whl (11 kB)
WARNING: pytgcalls 0.0.6 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.5-py3-none-any.whl (11 kB)
WARNING: pytgcalls 0.0.5 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.4-py3-none-any.whl (11 kB)
WARNING: pytgcalls 0.0.4 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.3-py3-none-any.whl (10 kB)
WARNING: pytgcalls 0.0.3 does not provide the extra 'telethon'
  Using cached pytgcalls-0.0.2-py3-none-any.whl (10 kB)
WARNING: pytgcalls 0.0.2 does not provide the extra 'telethon'
ERROR: Cannot install pytgcalls[telethon]==0.0.10, pytgcalls[telethon]==0.0.11, pytgcalls[telethon]==0.0.12, pytgcalls[telethon]==0.0.13, pytgcalls[telethon]==0.0.14, pytgcalls[telethon]==0.0.15, pytgcalls[telethon]==0.0.16, pytgcalls[telethon]==0.0.17, pytgcalls[telethon]==0.0.18, pytgcalls[telethon]==0.0.19, pytgcalls[telethon]==0.0.2, pytgcalls[telethon]==0.0.21, pytgcalls[telethon]==0.0.22, pytgcalls[telethon]==0.0.23, pytgcalls[telethon]==0.0.24, pytgcalls[telethon]==0.0.3, pytgcalls[telethon]==0.0.4, pytgcalls[telethon]==0.0.5, pytgcalls[telethon]==0.0.6, pytgcalls[telethon]==0.0.7, pytgcalls[telethon]==0.0.8, pytgcalls[telethon]==0.0.9, pytgcalls[telethon]==1.0.0, pytgcalls[telethon]==2.0.0 and pytgcalls[telethon]==2.1.0 because these package versions have conflicting dependencies.

The conflict is caused by:
    pytgcalls[telethon] 2.1.0 depends on tgcalls==2.0.0
    pytgcalls[telethon] 2.0.0 depends on tgcalls==2.0.0
    pytgcalls[telethon] 1.0.0 depends on tgcalls==1.0.0
    pytgcalls[telethon] 0.0.24 depends on tgcalls==0.0.16
    pytgcalls[telethon] 0.0.23 depends on tgcalls==0.0.16
    pytgcalls[telethon] 0.0.22 depends on tgcalls==0.0.15
    pytgcalls[telethon] 0.0.21 depends on tgcalls==0.0.14
    pytgcalls[telethon] 0.0.19 depends on tgcalls==0.0.12
    pytgcalls[telethon] 0.0.18 depends on tgcalls==0.0.12
    pytgcalls[telethon] 0.0.17 depends on tgcalls==0.0.11
    pytgcalls[telethon] 0.0.16 depends on tgcalls==0.0.10
    pytgcalls[telethon] 0.0.15 depends on tgcalls==0.0.10
    pytgcalls[telethon] 0.0.14 depends on tgcalls==0.0.10
    pytgcalls[telethon] 0.0.13 depends on tgcalls==0.0.9
    pytgcalls[telethon] 0.0.12 depends on tgcalls==0.0.8
    pytgcalls[telethon] 0.0.11 depends on tgcalls==0.0.7
    pytgcalls[telethon] 0.0.10 depends on tgcalls==0.0.6
    pytgcalls[telethon] 0.0.9 depends on tgcalls==0.0.5
    pytgcalls[telethon] 0.0.8 depends on tgcalls==0.0.4
    pytgcalls[telethon] 0.0.7 depends on tgcalls==0.0.4
    pytgcalls[telethon] 0.0.6 depends on tgcalls==0.0.4
    pytgcalls[telethon] 0.0.5 depends on tgcalls==0.0.3
    pytgcalls[telethon] 0.0.4 depends on tgcalls==0.0.3
    pytgcalls[telethon] 0.0.3 depends on tgcalls==0.0.3
    pytgcalls[telethon] 0.0.2 depends on tgcalls==0.0.2

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts
(AfterJailVoice2) sypherwork@sypherwork3080:~/Desktop/work_after_jail/JoinVC$