Gutenberg Block Editor not working on WP 5.4.1

Hi guys!

I’ve been happily using the LifterLMS course builder for the past three weeks. Although it”s my first attempt to building an e-course website and business your awesome plugin helped a lot, as I got the website to a 70% completion rate in no time, with no web design experience.

However, for like a week now I encountered a very strange problem and I can’t seem to figure it out on my own.
So, when I created my courses initially, I suppose I used WP Editor to edit the preview page of each course. I could add preset things to it such as Course Information (difficulty, completion time, etc), Author’s Info, Course Syllabus and the “BUY NOW” structure.

?Now, it seems like the interface of the WP editor has changed or something?definitely happened, as I can not find those options anymore, it looks different too, even if I add a new course. The preview page looks differently and the all the options I had initially are now gone and had been replaced with others. I can’t follow any LifterLMS tutorial anymore because the options I get are not the same as what people use and talk about in tutorials. I definitely had Gutenberg when I first started with WP around a month ago. However, now I am using something different. Something that I don’t understand. ??
I tried re-installing the LifterLMS wizard but it doesn’t help.

?I’m just looking to edit the preview pages of the courses I already added.?But I can’t find the above mentioned LifterLMS boxes to it..?I can’t find them and add/edit/use them.

I definitely used Gutenberg a month ago when I created my courses but now it disappeared somehow. I downloaded the plugin too, activated it, doesn’t work for some terribly strange reason. I can also show you some images so you can see how my editor looks like.

I hope someone can help my noob ass!
Thanks in advance!