I have, in the past, written numerous posts extolling the virtues of writing groups. I still highly recommend them, especially for beginning writers finding their style and interests, and especially if the group includes writers further along the path than you are.
That said, there are also drawbacks. One of those is that often these groups (and writing courses alike) will develop a strong subculture of ‘writing rules’ which leads the group’s members to believe that only if they eradicate all adverbs, all instances of passive writing and all instances of characters looking at themselves in a mirror from their manuscript, it will be publishable.
Another writing group taboo covers the poor old infodump.
What, exactly, is an infodump? I found this link on Writing.com which covers the commonly-touted opinion. Much of what is mentioned on this page is correct. The reader doesn’t need to know everything, and it’s usually not a good idea to start off your story with a huge block of info. But, that said, this article takes a unanimously negative view of information in fiction, as if you should never add any. Wikipedia offers a more balanced view. For starters, it routs the search for ‘infodump’ to ‘exposition’, a much more values-neutral word. It also describes exposition as a ‘literary technique’, again, without attaching a value. And it notes that exposition can be very useful. To this, I would add that if you write Science Fiction or fantasy, it is often mandatory.
If I write a story that involves, for example, the construction of a space habitat at the Earth-Sun L4 LaGrange point, I bet my readers are going to be mightily annoyed if I don’t explain somewhere in the story just what exactly L4 is and why one would locate this habitat there. That doesn’t mean I will start the story with that explanation to make sure the reader knows before the story starts. It means I need to explain where the information is needed when the reader needs it.
A similar situation will exist in fantasy. You need to explain your magic system, your class system, your hierarchy of gods, because the readers can’t even begin to understand how the world works from half a hint here or there.
The explanation could take various forms. It could be straight narration (very efficient). It could be one character talking to another (more dynamic). Or it could involve a scene. The latter would be most elegant, but you can’t do it for every single little fact without both blowing out your word count and slowing the plot to a crawl. This means that sometimes you have to lecture. Bad, bad, writer! Nah, really? What a load of BS.
These bits of information, worldbuilding, made-up or real, are what attracts readers to SF and fantasy. They want to learn about weird worlds, therefore, show them weird worlds. Show them where they need the information to fully appreciate the story. Show them in as active a way as you can make it. Sometimes, the most effective way is a full-scale lecture in orbital mechanics. Sometimes it involves a character giving a lengthy narration of the history of a kingdom, or a lesson in elemental magic, or having two characters discuss the course of the Second World War in the Pacific for five pages. Guess what? If it’s been clear from the outset that you were writing hard SF, or historic fantasy, or high fantasy, historical fiction or any genre that includes settings that are not those we’re familiar with in our day-to-day lives, this is exactly the reason why your readers are reading this stuff.
Embrace your infodumps. Your fiction needs them.