Accessing Meta services via public wi-fi with no MFA: security and other risks

For a moderately risk-averse user, what are the implications of signing into Instagram via public wi-fi in multiple locations across Europe? I am concerned about security and about Instagram flagging my account for suspicious activity. Note that each concern is unrelated to the other.

I am considering using a Chromebook in guest mode with no VPN. I believe I have heard that Instagram frowns upon VPN usage. Also, configuring a VPN in guest mode does not seem possible or practical. Alternatively, I could use another notebook running Fedora.

Even if Instagram allows multi-factor authentication, I don't plan to travel with a phone. I have had Instagram for a year and only accessed it via my home desktop in USA.