Struggling to get rails working

If I use "sudo gem install rails", it says everything is installed

Then I hit "rbenv rehash" and try to create a new project. The CLI gives me the error:

Rails is not currently installed on this system. To get the latest version, simply type:

$ sudo gem install rails

If I don't use "sudo" I get:

ERROR: While executing gem ... (Errno::EACCES)
Permission denied @ dir_s_rmdir - /usr/local/lib/ruby/gems/2.7.0/gems/actioncable-6.0.3.2

What's going on? How can I start again?

I feel like it's not looking in the right place to find rails

I changed the permissions on the directories and it no longer throws the ERROR message:

$ sudo chown -R $(whoami) /usr/local/lib/ruby/gems/*

However,
$ rails new project

Still throws:
"Rails is not currently installed on this system. To get the latest version, simply type:

$ sudo gem install rails"

There is Ruby 2.6.0 (/usr/lib/ruby/) and Ruby 2.7.1 (/.rbenv/versions/2.7.1/lib/ruby/) installed on my machine.

It could be pointing to 2.6.0 instead of 2.7.1, it looks like the gems are installed properly on the 2.7.1 version

Webpacker successfully installed!!

I don't know what happened but I uninstalled rbenv in brew and reinstalled in, reran the doctor and it seemed to work:

This page was immensely helpful - https://github.com/rbenv/rbenv#locating-the-ruby-installation

I was about to turf it all and setup a venv