Could you not use a telephone intent, where the meeting ID is the suffix to the dial in number with commas for any necessary pauses? Skype for business meeting invites have this. Zoom might then support inviting mobile phone conference participants using SMS, containing the link (think weak 2FA).
The most secure computer is a non-networked standalone box sunk in concrete sunk hidden at the bottom of a deep sea trench. It is not, however, very usable.
Example: tel://18005551212,,<meeting_id>#