Does anyone know how to modify Shreddit?

Like from https://kbin.social/m/RedditMigration/t/34112/Updated-Reddit-is-quietly-restoring-deleted-AND-overwritten-posts-and#entry-comment-140501

https://github.com/jdbassa/Shreddit
https://aur.archlinux.org/packages/python-shreddit-git

I really want to use this, but I have a couple of additional requirements:

First, to save a copy of my content locally on my hard disk (somewhere, anywhere, any format is fine) before overwriting and deleting the comment/post. So that I can manually repost on kbin/fediverse later.

Second, one particular post and comment I'd like to exclude from deletion. I've already overwritten with my good-bye reddit message and - as it was my most popular post ever - like to leave it up so folks who used to go back to that post to see my advice will know where to follow up to find me again.

I'd actually prefer to leave all my comments up with just the modified message but I think I have too many for the tools to delete automatically - instead I'd have to delete, wait a bit for the queue to refresh, then delete again as older comments start showing up on the API.

And I'm not confident that Reddit will get back to me before July 1 about my data retrevial request, which might make automatically deleting much harder.

Anyone know of a modified Shreddit that can handle these two requirements?