> Sometimes I see engineers showing up to the standup and having to remember and plan on the go.

Standups are not "iceberg meetings." By having the team prepare for the standup all week you might be discussing things that have been organically solved, or that aren't pertinent to you or the rest of the team. If you care enough about something, you'll remember to bring it up during standup. If you take the old-school 2 hour Monday morning status meeting and call it a standup then you aren't doing standups.

If you need that thorough 2 hour status meeting, abandon agile. Don't put your engineers through the hell of reporting to two status update workflows.