Could this plugin do more harm than good?

Hi all! I'd like to start this off by stating I'm not very well versed when it comes to SEO. I handle the marketing for a mid sized company and had to figure most things out by myself.

Here's the situation; we've recently updated our WordPress website almost entirely from the ground up. As such, I've noticed we have a lot of missing alt texts in our old images. Being a one-man team, I was trying to find the most time-effective way to deal with this situation.

I ran into this plugin called 'Bulk Image Alt Attribute' which basically automatically replaces missing alt tags with either Post Title, Yoast Focus Keyword, Image Name or a combo of Yoast and Post Title.

But wouldn't setting it as Post title be harmful to SEO? Especially if you end up having more than one image with the same alt text?

Just a suspicion I had and was wondering if anyone could offer their opinions on this matter.

Thanks in advance!