Here issue is not with React but classic case of poor leadership, architecture and project planing.
All issues and road blocks could be avoided just with adhering to a few guidelines.
Roadblock #1: I am not even sure why does it matter what is behind the curtain, only important thing are REST contracts, everything else is splitting team front-end / back-end. Everyone can have what ever naming convention they want. If project is enterprises it means that has more than 11 people or what is considered as a high number of SCRUM team, so spiting concerns is important and necessary. Everyone does it all (all full-stack devs) just does not work.
Roadblock # 2: This is due to experience, and it is up to UI team lead to decide, rest they follow. Sorry, in enterprise projects democracy does not work, maybe in the first few meeting but there you need to draw a line. Regarding dependencies, this is strictly role of one person, everyone else works on 'git pull' forbid everyone else to fiddle with package.json use lock file strictly and package versions, and you will not have any issues, each machine will have exact copies.
Roadblock # 3: This is not a blocker and Hooks have solution for any kind of pattern, it is still possible to use Redux pattern without issue.
Roadblock # 4: Machines can get slower, and in my team we had similar issues, but hey you cannot expect to work with 2GB in 2020, not realistic especially with Chrome sucking memory with 34 tabs open. Don't forget VS Code is built based on Chromium so basically you have two vampires on you computer. And having virtualized environment is even worse.
Roadblock #5: Saga in my case was relief, if you structure correctly Redux Actions and Reducers in neat way, and if you split your concerns, you do not have any issue, in fact it was working as a charm.
Again there are multiple approaches how to deal with this, even split project in multiple smaller SPAs if necessary, but at any point not issue with React but more
case of PEBMAC :/sorry.