There are tons of horror stories about OCI's free tier (check r/oraclecloud on reddit, tl;dr: your account may get terminated at any moment and you will lose access to all data with no recovery options). I wouldn't suggest putting anything serious on it.
They will not even bother sending you an email explaining why, and you will not be able to ask it, because the system will just say your password is incorrect when you try to login or reset it.
If you are on free tier, they have nothing to lose, only you, so be particular mindful of making a calendar note for changing your CC before expiration and things like that.
It’s worth paying for another company just for the peace of mind of knowing they will try to persuade you to pay before deleting your data.
Are all of those stories related to people who use it without putting any payment card in? I’ve been happily siphoning Larry Ellisons jet fuel pennies for a good year and a half now and have none of these issues because I put a payment card in
IME, the vast majority of those horror stories end up being from people who stay in the "trial" tier and don't sign up for pay-as-you-go (one extra, easy step) and Oracle's ToS make it clear that trial accounts an resources can and do get terminated at any time. And at least some of those people admitted, with some prodding, that they were also trying to do torrents or VPNs to get around geographical restrictions.
But yes, you should always have good backups and a plan B with any hosting/cloud provider you choose.
