Hi jacque101,
If you're still experiencing slowness in the Mail app on your iPhone and iPad, try to remove your email account and set it up again. Your email may need to be re-provisioned after the recent update.
It's very important that you confirm your account is an IMAP account before taking this step. Removing a POP account may cause data loss.
Remove your email account and set it up again
1. On your computer, sign in to your email provider’s website. Make sure that all of your email is there or make sure that your email is saved somewhere other than your device.
2. On your device, go to Settings > Mail, then tap Accounts.
3. Tap the email account that you want to remove.
4. Tap Delete Account.
5. Add your account again.
If these steps don't work, contact your email service provider for more information.
If you can't receive email on your iPhone, iPad, or iPod touch - Apple Support
If you've already tried this step, outline everything you've already tried. We don't want to ask you to retrace your steps.
Kindest Regards.