Why are emails so slow on my ipad?

Your Mail settings will have significant influence upon how often your email will be retrieved from your mail server. There are several setting that influence the frequency of email message retrieval.

From your description, it is possible to infer that your mail provider does not provide “push” mail - and instead your email is “fetched” by your mail client. For iPad, you have a choice of settings:

Settings > Mail > Accounts > Fetch New Data

Automatically

When set to Automatically, your iPad will only attempt to automatically retrieve email when the iPad is connected to its Power Adapter. This setting is power-efficient, in that email is only retrieved on-demand - or if external power is available to the iPad.

Manually

When set to Manually, the iPad will only retrieve Mail from the mail server when the Mail App is accessed - or manually refreshed (a downward finger-swipe gesture within the selected mailbox).

Hourly/Every 30 minutes/Every 15 minutes

With any of these settings, the iPad will retrieve email to a fixed schedule.

Just one suggestion and that is to check that emails are set to ‘Push’ (Mail\Accounts\Fetch New Data) and Also set to ‘Automatically’.