以下リンク先にある内容を実行した後、今回の問題に遭遇しました。

rails sした時にalready initialized constant FileUtils::VERSIONとwarningが出てくる - Qiita

railtiesを5.2.3にすれば解決できるのかと思い、railties 6.0.0の対象と思われるディレクトリ削除や対象のgemのアンインストールなどしてみましたが、結果は変わらず、上のようなエラーが出てしまいます。

railsコマンド実行時に表示されたエラー

$ rails s
Traceback (most recent call last):
        1: from /Users/pc/.rbenv/versions/2.5.1/bin/rails:23:in `<main>'
/Users/pc/.rbenv/versions/2.5.1/bin/rails:23:in `load': cannot load such file -- /Users/pc/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.0/exe/rails (LoadError)

実行環境 (ローカル)

Rails 5.2.3
Ruby 2.5.1

#!/usr/bin/env ruby
#
# This file was generated by RubyGems.
#
# The application 'railties' is installed as part of a gem, and
# this file is here to facilitate running it.
#

require 'rubygems'

version = ">= 0.a"

if ARGV.first
  str = ARGV.first
  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
    version = $1
    ARGV.shift
  end
end

if Gem.respond_to?(:activate_bin_path)
load Gem.activate_bin_path('railties', 'rails', version) #23行目
else
gem "railties", version
load Gem.bin_path("railties", "rails", version)
end

Gemfile

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.5.1'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.2.3'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use Puma as the app server
gem 'puma', '~> 3.11'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'

# CSSフレームワークとして追加
gem 'materialize-sass', '~> 1.0.0'

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'mini_racer', platforms: :ruby

# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.2'
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.5'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use ActiveStorage variant
# gem 'mini_magick', '~> 4.8'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', '>= 1.1.0', require: false

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '>= 3.0.5', '< 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

group :test do
  # Adds support for Capybara system testing and selenium driver
  gem 'capybara', '>= 2.15'
  gem 'selenium-webdriver'
  # Easy installation and use of chromedriver to run system tests with Chrome
  gem 'chromedriver-helper'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]