iFrame code in HTML blocks were wiped out

I didn’t think too much of this issue initially, but I now realize it is an even bigger problem than anticipated. I had an issue with version 2.13.9 previously that was resolved with 2.14.0. But it seems like there is another problem with the newest update, which the database refresh might have caused.

Since my blog is a travel blog, I always include the iFrame code in the HTML block to show a map of places I have visited. But from 2.13.9 to 2.14.0, I realized that the iFrame codes in my HTML blocks were all removed!

I have included a page here for your reference. There is an iFrame code under the second H2 heading of this post, and is just one of the many blog posts that are affected on my blog: https://theordinarykatalog.com/hokkaido-itinerary-a-day-trip-to-the-charming-otaru/

I have over 200 posts, and I am not about to go through each one to put in the iFrame codes again. So, I would like to know how to proceed from here besides rolling back using my web hosting service. Note: I tried rolling back using the Spectra plugin, but it wouldn’t work since I think the iFrame codes were wiped completely after the database refresh.

I am so close to changing to another block editor because since switching to Spectra, I couldn’t stop worrying about issues that might happen to my blog.