Some suggestions:
Consider using a NAS like
QNAP's TS-251B. Point the cameras in Configuration>Storage>Storage Management>Net HDD to save images to the NAS. Then load
QNAP's Cloud Drive App on the NAS and connect it to your Google Drive. From there you should be able to sync the files. The app has options for scheduling but I'm not sure it allows automatic deletion of files older than X amount of days. With a little familiarity of Linux you can connect to the NAS via SSH and create a cron job that will manage file retention.
Synology's NAS offerings may also be an option.
Using a
Raspberry Pi is also an option if you have some experience with Linux. The procedure would be similar to the above at a much lower cost. They are very economical to run 24/7, are wall mountable and easy to conceal if required. If you prefer working with Windows, there are plenty affordable
micro PC's available online.
Intel's NUC range offers higher spec, mini PC's that I find are reliable but are expensive. Connecting any of these to your LAN with a scheduled script to manage file retention would be a doddle and my preferred solution.
Another possibility is to use a FTP server. If you have a company website your hosting company 'should' already have setup one up for your website. If not, you could use
Google Cloud and set one up for free* (read the Terms!). Going the Google Cloud route requires you to install and configure a Linux VM. Either way, the cameras could be configured to save images to the FTP server. Then using one of the many cloud drive management services (some are free provided you don't go over 30GBs a month) you could sync your Google drive with the FTP server. Not sure how you would manage file retention unless you have shell access to the FTP server.
I haven't tested any of the above so some due diligence is needed. Security is also a major factor especially when using third-party cloud services. I plan to test the Google Cloud route in the next few days as I already have a Linux server setup. I'll keep you posted.
