How do I fix 'No Mail' and blank screen in Mail App on iOS 18.4.1?

No longer receiving emails on the Mail App. Same email addresses I’ve had for years. Updated to iOS 18.4.1 and still nothing but a blank screen which says No Mail. Scroll down to update and it says connecting… and then updated just now, still with no mail. Does anyone have any suggestions? I have updated, rebooted, uninstalled and reinstalled my email addresses… not sure what else to do

[Re-Titled by Moderator]