Full disclaimer, I am the author of the WordPress plugin I am about to mention and I am hoping this answer would give it more visibility.
So, I had to do this for a few clients last year mostly for SEO reasons and it was getting ridiculous. I made a WordPress plugin that can do just what you asked. Bulk update all WordPress image attributes in one go. You can find it here: https://imageattributespro.com
What it does is, it goes image my image, finds all the posts where the image is inserted into and then updates the alt text and image title right within the post.
Uses WordPress functions to do all these, so never had any issue like a corrupt database or anything. But obviously its a good practice to backup your db before you update anything in bulk.
There is option to update only what isn’t already updated, so for all the images that you have custom stuff already in place, they won’t be affected at all.
You can see a video of this in action:
Hope that helps. If you have questions, do let me know 🙂