It can be done remotely but its not straight forward it is also time consuming, but i have used it as a last resort when apps will not download via downloader etc.
1: You need either team viewer or anydesk installed on your laptop/computer/Mac and at remote end as well
2: Login to remote machine with remote access
3: download the app you require to install via the remote laptop/mac
4: Download adb tools via remote machine (you may need to install adb drivers as well)
5: find out the ip address of the firestick on remotes machine
6. Type the command: adb version. on remoe machine via team viewer,If ADB has been installed, you will find Android Debug Bridge and its version.
7. Type the command adb kill-server on the remote machine via team viewer on the Windows PC or Mac computer.
8. Type the command adb start-server on the remote machine via team viewer on the Mac or Windows computer.
9. Type the command adb connect <ipaddress> of the firestick on the remote machine via team viewer on the windows or Mac Computer.
10. To ensure you are connected.
Type the command: adb devices on the remote machine via team viewer
Only one device should appear – the one whose IP address you entered.
11: Enter the command on the remote machine via team viewer:
adb install <path-to-apk-file>Be sure to replace <path-to-apk-file> with the full path to the APK file you wish to push and install
Wait a while this will push the app and install to the firestick. You should get a confirmation message saying app installed or transfer completed.