Hi @Everton 292929, I hope you're doing well!
Please be aware that if your account is ever downgraded, Dropbox will not delete any of your files, so there is no risk there.
Now, with that being said you can either keep the Basic account, however with 156GB you will have no space to make any changes in the account, or you can choose one of our individual plans.
If you have any questions, let me know!