Its secure defaults will probably block all other services you're running on your server and render them inaccessible.
You might even end up not being able to ssh to your server if you choose not to let Algo set up ssh configurations (because you have your own).
I would say install Algo on a dedicated droplet or backup your VPS before setting it up.
If you are running other co-resident services and need more lenient firewall rules / system configuration, you should consider another option.
droplet == host?
Its secure defaults will probably block all other services you're running on your server and render them inaccessible.
You might even end up not being able to ssh to your server if you choose not to let Algo set up ssh configurations (because you have your own).
I would say install Algo on a dedicated droplet or backup your VPS before setting it up.