diff --git a/.rubocop.yml b/.rubocop.yml
index 61765c3323f..a34949cea87 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -120,6 +120,12 @@ Performance/CollectionLiteralInLoop:
     - 'Rakefile'
     - 'spec/**/*.rb'
 
+Performance/EndWith:
+  SafeMultiline: false
+
+Performance/StartWith:
+  SafeMultiline: false
+
 RSpec/StubbedMock:
   Enabled: false
 
diff --git a/lib/rubocop/cop/layout/end_of_line.rb b/lib/rubocop/cop/layout/end_of_line.rb
index 6b113df480d..879fc54e550 100644
--- a/lib/rubocop/cop/layout/end_of_line.rb
+++ b/lib/rubocop/cop/layout/end_of_line.rb
@@ -65,7 +65,7 @@ def on_new_investigation
 
         # If there is no LF on the last line, we don't care if there's no CR.
         def unimportant_missing_cr?(index, last_line, line)
-          style == :crlf && index == last_line - 1 && !/\n$/.match?(line)
+          style == :crlf && index == last_line - 1 && !line.end_with?("\n")
         end
 
         def offense_message(line)
diff --git a/lib/rubocop/cop/metrics/utils/abc_size_calculator.rb b/lib/rubocop/cop/metrics/utils/abc_size_calculator.rb
index ca873c188fe..869b586a1f5 100644
--- a/lib/rubocop/cop/metrics/utils/abc_size_calculator.rb
+++ b/lib/rubocop/cop/metrics/utils/abc_size_calculator.rb
@@ -121,7 +121,8 @@ def simple_assignment?(node)
           end
 
           def capturing_variable?(name)
-            name && !/^_/.match?(name)
+            # TODO: Remove `Symbol#to_s` after supporting only Ruby >= 2.7.
+            name && !name.to_s.start_with?('_')
           end
 
           def branch?(node)
diff --git a/lib/rubocop/cop/style/combinable_loops.rb b/lib/rubocop/cop/style/combinable_loops.rb
index 7099436f8ee..74d566ab85d 100644
--- a/lib/rubocop/cop/style/combinable_loops.rb
+++ b/lib/rubocop/cop/style/combinable_loops.rb
@@ -75,8 +75,9 @@ def on_for(node)
         private
 
         def collection_looping_method?(node)
-          method_name = node.send_node.method_name
-          method_name.match?(/^each/) || method_name.match?(/_each$/)
+          # TODO: Remove `Symbol#to_s` after supporting only Ruby >= 2.7.
+          method_name = node.send_node.method_name.to_s
+          method_name.start_with?('each') || method_name.end_with?('_each')
         end
 
         def same_collection_looping?(node, sibling)
diff --git a/lib/rubocop/cop/style/redundant_self_assignment.rb b/lib/rubocop/cop/style/redundant_self_assignment.rb
index d02accc55ef..f040aa7da66 100644
--- a/lib/rubocop/cop/style/redundant_self_assignment.rb
+++ b/lib/rubocop/cop/style/redundant_self_assignment.rb
@@ -66,8 +66,8 @@ def on_lvasgn(node)
         alias on_gvasgn on_lvasgn
 
         def on_send(node)
-          # TODO: replace with #end_with? after supporting only ruby >= 2.7
-          return unless node.method_name.match?(/=$/)
+          # TODO: Remove `Symbol#to_s` after supporting only Ruby >= 2.7.
+          return unless node.method_name.to_s.end_with?('=')
           return unless redundant_assignment?(node)
 
           message = format(MSG, method_name: node.first_argument.method_name)