The easiest way I can think of would probably be adjusting editor habits to always include valid times in the date entries for both tasks/meetings. Task end dates could be EOD (unless a hard deadline is a meeting or something else).
You can enable time on the date field when configuring the field settings:
And then editors can adjust the time by double clicking on the time value in the cell:
Re: the Gantt view, milestones if enabled work by only supplying an end date. So this makes me think you might use the same end-date-only approach for meetings (depending on if you're syncing to an external calendar like outlook/google calendar, this might not be better but I haven't tested this).
Personally, I probably would only include BAU stage gate meetings as "tasks" that are part of the standard process for projects in Airtable. Like if a review meeting or approval meeting was always part of the process. If I wanted a record of all meetings that were held to support a task, I would create a separate table to link to tasks or just keep a long-text Notes/Action Items field updated after each meeting.
