I want to reset Apple Mail (Ventura), but I have a lot of questions about how to do it thoroughly and still save my mailboxes that are on my Mac.....

Been having a lot of problems with Apple Mail in Ventura. Moving things to the trash (using my Mac) seems to hang for a long time, even for just one or two messages. I'm getting a lot of "this message has no content" on my Apple Mail on my MacBook Pro, but the same message is fine on my iPhone or web-based iCloud mail.

I've rebuilt all the iCloud mailboxes, and the inbox has been rebuilt twice. I also deleted the iCloud account once and re-added it. It takes forever (OK I do have too many messages) but even trying to move those messages off of iCloud to my "on my Mac" mailboxes is taking too long. Last time it took over two days to rebuild the InBox. OK it did have about 50K messages, but that was down from the 100K+ I had about two weeks ago. My internet is Starlink (usually 50mbps or better), so the amount of time seems way to long for the files sizes we are talking about. iCloud reports my current mail usage is about 13GB. I I know it won't happen that fast, but 13GB should only take minutes at 50mbps, not days.

So now that I've pared down my mail quite a bit, I want to save all my "on my Mac" mailboxes to a new folder, and then basically reset the Mail app completely. Then re-add the iCloud account, and then re-import the mailboxes that are saved on my Mac.

So here are my questions:

Question #1 I don't need to "export" those mailboxes do I? Can't I just copy them? I know how to find the mail folders for those mailboxes, I can copy them to another folder or external drive. Later on I can import those mail boxes and just select the "Apple Mail" option when importing correct?

Question #2 How to reset Apple Mail to factory defaults? I know I need to turn off my iCloud mail account in system preferences.

I have seen several articles/posts about manually resetting the Mail by using Command + Shift + G and then going to:

~/Library/Containers

~/Library/Mail

~/Library/Preferences

~/Library/Application Scripts

and removing deleting "all things" related to mail app. One set of instructions said "all folders" in ~/Library/Containers, but then said "all things" related to the mail app later on. This is a bit scary, I am afraid of deleting things I need. Some more advice here would be helpful!!!

After that I would restart my MBP, and go to System Settings and turn my iCloud Mail back on, then launch the mail app......and wait, hopefully less time than before. Then import the "on my Mac" mailboxes again.

Does all this make sense? Anything else I should do to ensure success? This has already taken way too much time, I want to "do it right"!!!!!

Thanks in advance and have a great day!