I would ignore such warning message if Electrum can run normally. In fact, many application (and even your OS) will show few warnings, but usually you can run it without facing any problem.
Thanks for your clarification and assurance.
Thanks for your warning about uninstalling "urllib3".
By "urllib3", did you mean "python3-urllib3" ? Debian 10 has a package called "python3-urllib3 (1.24.1-1)" but not "urllib3".