Update to Catalina, Mail using excessive memory, cannot use Mail

Have sorted out my Mail issues. No updates from Apple to tackle this. No help from their support.

The only way to do it is to rebuild everything. Sigh.

The Issues:

1. Mail ramps up to defcon 5 using 100% of RAM capacity, thereby rendering all other apps useless, or very slow
2. Mail taking almost a minute to bring up the Print dialogue box to print or Print to PDF which I often require for major projects
3. Mail not turning unread notification off after clicking on message, remains as unread with notification dot in Mail list
4. Mail unable to show accurate unread message count in dock icon
5. 
   

Here is the process I went through... in the hopes it might help others. Most is not new to anyone who has rebuilt their Mail from the ground up. I used to do this with each new system, haven't done so for a system catastrophe such as Catalina has brought on. A few things have changed with Mail -- possibly in earlier OS versions, just haven't encounter this to notice.

Rebuild Mail in Catalina:

1. Archive all Mail -- Control+click folders and export as mbox files.
2. Quit Mail. Do not start Mail again until all steps complete.
3. Navigate to Library folder -- Option+click Go menu at Finder to reveal Library folder in list. Find Mail folder. Back up by copying to another location and/or another drive.
4. Delete Mail folder from Library after making backup.
5. Optional -- delete Internet Accounts [if you want a really clean start]
6. Restart.
7. Start Mail and you should see the Create New Mail Accounts window. Create each new account you require.
8. Import saved mbox mail -- will appear in a folder called "Import"
9. Move imported mail messages to inbox if you want more recent mail readily accessible. Suggest no more than 10-20 at a time to give the mail server time to ingest old messages.

NEW:

1. Mail signatures -- no longer reside within the Mail folder, so these will remain active in Mail, you just need to reassign to new email accounts if you removed them [step 5 above].
2. Junk Mail Filters -- no longer reside within the Mail folder, so these will remain active, however, you will need to rebuild all of the folders you may have used to redirect any messages into, since these folders were within the Mail folder that was removed.

RESOLVED:

1. Mail no longer ramps up to defcon 5 taking all resources and slowing all other apps to a crawl.
2. Mail now actually turns the unread notification off when you read a message
3. Mail now accurately shows the number of unread messages in the dock Mail icon
4. Mail now prints to PDF quickly
5. Mail now saves the entire message to a text file when saving, instead of just the header and blank message

I hope this helps others having problems with Mail and Catalina, as Apple does not appear to know how to handle or offer any update to remedy this issue.

If anyone has any comments to improve the method outlined here, by all means, feel free to offer suggestions.

Thanks.