Well, the answer is, yes, you can. Though it is best if you have installed Garmin Express, you can update Garmin maps without it as well. For this, you need to create MyGarmin account. The rest of the process is pretty smooth.
Go to www.mygarmin.com and create a myGarmin account.
Next, log in to your account and register your Garmin device.
After that, click on the myMap tabs and add the updates to the cart.
Now, purchase the selected updates or if the updates are free of cost, click on the download tab directly.
Install the downloaded updates on your device.
Please read the originial post here: https://gps-map-updates.com/garmin-map-updates/