Error while running vagrant up command

Running vagrant up isn’t working anymore. I have read the post Vagrant up command not working which instructs removing Virtual Box and installing the newest version. However, I can’t uninstall VB either. Then I downloaded new version of VB here, and when I doubled clicked on it I got the error message: VirtualBox-6.1.0-135406-OSX.dmg image not recognized.

Some commands I’ve ran.

Leines-MacBook-Pro:~ cozymachete$ vagrant up
Vagrant failed to initialize at a very early stage:

The "VBoxManage" command or one of its dependencies could not
be found. Please verify VirtualBox is properly installed. You can verify
everything is okay by running "VBoxManage --version" and verifying
that the VirtualBox version is outputted.

If you're on Windows and just installed VirtualBox, you have to
log out and log back in for the new environmental variables to take
effect. If you're on Linux or Mac, verify your PATH contains the folder
that has VBoxManage in it.
Leines-MacBook-Pro:~ cozymachete$ vagrant --version
Vagrant 2.2.6
Leines-MacBook-Pro:~ cozymachete$ uname
Darwin
Leines-MacBook-Pro:~ cozymachete$ which virtualBox
/usr/local/bin/virtualBox
Leines-MacBook-Pro:~ cozymachete$ sudo ps aux | grep -i "vbox"
Password:
cozymachete       3214   0.0  0.0  4277496    676 s001  S+   12:36PM   0:00.00 grep -i vbox
Leines-MacBook-Pro:~ cozymachete$ sudo apt-get remove --purge virtualbox 
sudo: apt-get: command not found
Leines-MacBook-Pro:~ cozymachete$ sudo apt-get update
sudo: apt-get: command not found
Leines-MacBook-Pro:~ cozymachete$ lsb_release -a
-bash: lsb_release: command not found
Leines-MacBook-Pro:~ cozymachete$ lsb_release -d
-bash: lsb_release: command not found
Leines-MacBook-Pro:~ cozymachete$ cat /etc/issue
cat: /etc/issue: No such file or directory
Leines-MacBook-Pro:~ cozymachete$ vagrant box add hashicorp/bionic64
Vagrant failed to initialize at a very early stage:

The "VBoxManage" command or one of its dependencies could not
be found. Please verify VirtualBox is properly installed. You can verify
everything is okay by running "VBoxManage --version" and verifying
that the VirtualBox version is outputted.

If you're on Windows and just installed VirtualBox, you have to
log out and log back in for the new environmental variables to take
effect. If you're on Linux or Mac, verify your PATH contains the folder
that has VBoxManage in it.
Leines-MacBook-Pro:~ cozymachete$ 

Thank you!