Ive seen people dislike Endfield and some might say they hate it. Personally i think endfield is just factorio with Gacha but is the criticism justified?
There are two different audiences coming in with different expectations and both being disappointed.
You have Arknights fans coming in who were expecting more Arknights but with higher production values. They were let down. Arknights had moody visuals and vibe. The game starts off with the Doctor being extracted from a city that is destroyed by a riot and terrorists, and then they go to not-Hong Kong where Ch'en's uncle Wei Yenwu has to order the execution of the ghettos so he can get the Yanese inspectors off of his back and retain the country's autonomy. Silverash is a corporate overlord/shadow dictator trying to industrialize his country ASAP so it does not get annexed by the greater powers. And so on. There are many countries and while most of them are just ripoffs of real life countries, that riff allows you to fill in the gaps and makes the setting feel like it has verisimilitude, like it really exists.
Endfield takes place on what feels like a freshly colonized planet in which there are so far only two countries. It also definitely suffers from Genshin scale issues where you see one "city" and that is pretty much the extent of the "country". The Endfield countries do not have bloody or corruption or economic problems like the Arknights countries did. There is no war. There are no cities being wiped off the face of the earth. No one faces the same no-win scenario that Wen or Silverash did. Etc. The aesthetic and vibes is light and fun. Also, all of Endfield's cast looks to be in the same vein as Genshin's, which is that everyone is a young slim beautiful person in their teens or early 20s. Whereas Arknights had variety with guys in their 30s, old guys, robots, etc.
Lastly, you have disgruntlement about the gameplay. Arknights differentiated itself from all of these other gachas (usually 4 guys in a row like a Famicom Final Fantasy game) by being a tower defense game, so it had more involved gameplay. The beta for Endfield was a bit more real-time-with-pause combat as you could freeze time to aim another party member's skillshots. But that was thrown out and the final game is another shallow Genshin-like where you just mash your 3 buttons, your basic attack/skill/ultimate.
There is just not much to latch onto here if you are an Arknights fans.
For the Genshin audience coming in, it is hard to justify switching to Endfield. This game came out 6 years after Genshin and people are already invested in that (or HSR, or WuWa, or maybe ZZZ). Endfield has a little higher production values but is otherwise the same game, and ultimately does not seem to be as appealing. The base building is so shallow it mind as well not exist.
Genshin launched with the Teyvat trailer that promised a story with a beginning, a middle, and an end and previewed the 7 countries and their chapters, so people were looking forward to Snezhnaya, Natlan, Dendro expac, etc. HSR painted an imaginative space fantasy world with its three launch worlds and the blurbs in Simulated Universe. ZZZ goes for comfy Persona vibes. Endfield just has not managed to tantalize people enough, and it is unclear what the vision or endgame is or what people should be waiting for.
There is also a mild lack of confidence. The game was highly anticipated, but had a disastrous payment processing issue at launch that deterred people during the crucial customer acquisition period. After launch, the numbers plummeted and Endfield is consistently being beaten by Arknights on mobile, though Endfield is primarily played on console and PC so we don't have the full picture. But that there has been a source of contention and has made people wonder if Hypergryph will reduce Endfield's budget going forward, which makes people hesitant to invest in it.