Season 3 more season 1 vibes? Or is deviation fine?

I guess the deviations are not really that big so they can't be fixed.

• Is it really that important? The change made Rudeus look better than if he was the initiator, especially because he didn't want to be like Paul, so it makes more sense. Does it really change anything?
  
• It's easier to see that it's been some time since Rudeus was at home and it's at the very end of the season. Again, does it impact anything in the story?
  
• I'm not sure what do you mean by that. Because I haven't read the LN I can only speculate that he researched about hydra before the fight or searched the hydra after the fight to get some materials. First option may not matter if it has no actual purpose for later parts of the story and then I have no problem understanding the anime director to drop it from the adaptation. It could be a really boring part, but I think they made the rescue mission too short and it felt like they've dropped too much of source material. Possibly they had problem fitting the story into a season, but those could be implemented as flashbacks in the future.
  
• I wouldn't be so sure that they've skipped it. In the last episode they got back home and some events could be just moved around to complete this season. I hope that healing Zenith will have it's own arc and I think that it's quite likely that we'll see some development in the next season. This whole topic seems just too big to fit in 10 minutes.
  
• This is a big skip and I'm not sure if it's possible to fix this. They may make it happen, but changing the moment of this occurring sounds off to me so let's consider what they can do. Firstly, she may know that she's pregnant but she just hid that for some time, but this would kind of break the timeline as she should be easily 2 mths into it and it should be visible. Second option is to move her pregnancy later in the story, but this would change its meaning (accident vs planned). The last option is to skip it altogether. I have no idea how the story will be changed in the next season, but let's hope the changes they make aren't really that important to the plot.
  

I don't think that it matters at all what some random youtuber said and whether the studio should do as he pleases. Also it's not like they can change anything in 3rd season as it's already in production, which most likely means that they've agreed on the story line for the season and there are no chances for any change to be implemented. Since we don't know how much is going to be adapted, we can't reliably speculate for the 4th season. Moreover I believe they're doing their best job to make as much money as possible on this anime so they're doing their best job and make the best decisions in their opinion from the options they have available.