Imho you are a teacher and it is likely that you have confidential student data. Likewise, it is likely that your employer's data will not be seen by unknown third parties. After learning about the Google's and Alphabet's (mother enterprice) business model and studying carefully the Google Drive terms of service, you encrypt confidential uploaded data. May we know how and with what you do that?
Sorry, you are giving public "advice" and recommendations here, so you have to accept that things have to be looked at from more than one side (cheap, simple and convenient).
Convenient and halfway secure is to have data multiple times, offline and in several generations (versioning) at home and encrypted elsewhere. I don't care if it's at a notorious data octopus.
(Provided that 'home' is 'secure'.)
en.wikipedia.org
"Initially, Google granted itself the right to re-use user documents with its German-language T&Cs.[23] According to Google, this was a translation error.[24] The T&C section now assures copyright in its own content.[25] Google grants itself broad rights of use as well as publication, except "If you are in Germany and access Google products or services that are targeted at Germany."[26] It is not discernible from the outside at what point this condition exists.
Following the passage of the SESTA/FOSTA legislative package on 21 March 2018, Google blocked or deleted numerous pieces of "sexually explicit" content from Google Drive, citing its TOS.[27]"
de.wikipedia.org