If you have any questions, you can check out Manjaro and Arch forums and wikis. They both have large and helpful communities. On the other hand, 99% of the time, you will not need to visit the forums since you can find answers to most issues on Google anyway.
The statements like the last sentence is why you got a from me.
When I use a genral purpose search engine I will mostly find links to the Arch forum or the Manjaro forum and then I neet to visit them. Sites like Superuser are also often among the top results and then I don't need to go to the Arch or Manjaro forums. But the advices there are too often not applicable.
I also see no real argumentation in your text. You just tell "from my experience", "in my opinion", "I recommend". What a critical would read from such a lack in argumentation: Manjaro is a distro for people who don't know what they are talking about.
and you will want to stick with specific versions of those tools during your projects.
A meniton that on a rolling release distribution like Arch you will generally find only the newest version of a package. But with programming languages, compilers and other development tools they keep several major versions of the toolchain like
openjdk in its latest version 13.
Arch Linux and derivatives, especially Manjaro Linux, have the best of the best package managers. You can find any package and their supported version in main package repositories, and user-submitted ones.
I know that mean here what I wrote about openjdk, but what you write is vague and almost incorrect regarding "any".
To sum up: This text is an endorsement from an application developer who has made good experiences with Manjaro, but isn't a specialist in Linux OS field.