Budget isn't the issue(rarely ever is in anime production, yet anime fans still blame that every time). Either way I doubt most peoples criticisms of the series rest solely in the bad CGI & animation of the series. It seems to have cut and changed parts of the original LN. It would have been better if it was at least 2 cours. But It's also a pretty run-of-the-mill isekai with the same tropes.
As someone who watched the anime, read the manga, read the 10 volumes of the ln and then nearly finished the story in the WN, the story itself isn't a masterpiece but I enjoyed it, and he's supposed to become a super Chad in the afterstory, regardless, it's obvious half the animation budget went to bouncy physics if you know what I mean and not the fights, tho the biggest issue is that they put 4 volumes into 12 episodes and as a result skipped a lot of important things
it's obvious half the animation budget went to bouncy physics
it's not a matter of budget lol. Time & talent are the most important things when it comes to the quality of an anime.
One of the studios working on it was whitefox which we know can animate, both cgi and straight up drawing, we have gotten shows like re zero and goblin slayer, which showcase both animation and cgi capabilities. You are correct regarding the budget being around the same for shows, let me correct my previous statement and say too many resources were allocated to different things which left the fights, especially the one with the dragon lacking to say the least
I don't know the details of the production so I can only guess but it's possible the production window for the series was just to small. Also it's the individual talents involved on those productions that make them good, not white fox themselves.
It's been a long time and I only just now saw this Thread, but this might help out if it is still of interest
https://www.animenewsnetwork.com/interest/2019-07-10/arifureta-author-may-have-prompted-anime-staff-change/.148858
Basically the production was all over the place due to the author's displeasure.
I like the WN, didnt read the LN but noticed how much they messed up. It's not about budget but probably more about miscommunication and time management in this case, though thats just me assuming. Let's hope they do better in the 2nd season