diff --git a/README.md b/README.md
index d946533..f8f817b 100644
--- a/README.md
+++ b/README.md
@@ -91,7 +91,7 @@ These methods enable adding, removing, and modifying elements in the Collection.
   ```
 
   ```php
-  $collection ->add('X', 'Y', 'Z');
+  $collection->add('X', 'Y', 'Z');
   ```
 
 #### Removing elements
diff --git a/src/Internal/Operations/Order/Sort.php b/src/Internal/Operations/Order/Sort.php
index 0eab8f3..d310dc9 100644
--- a/src/Internal/Operations/Order/Sort.php
+++ b/src/Internal/Operations/Order/Sort.php
@@ -35,9 +35,7 @@ public function apply(iterable $elements): Generator
             : $this->predicate;
 
         $ascendingPredicate = static fn(mixed $first, mixed $second): int => $predicate($first, $second);
-        $descendingPredicate = is_null($this->predicate)
-            ? static fn(mixed $first, mixed $second): int => $predicate($second, $first)
-            : $predicate;
+        $descendingPredicate = static fn(mixed $first, mixed $second): int => $predicate($second, $first);
 
         match ($this->order) {
             Order::ASCENDING_KEY    => ksort($temporaryElements),
diff --git a/src/Internal/Operations/Transform/JoinToString.php b/src/Internal/Operations/Transform/JoinToString.php
index 68acb45..441aeff 100644
--- a/src/Internal/Operations/Transform/JoinToString.php
+++ b/src/Internal/Operations/Transform/JoinToString.php
@@ -19,6 +19,19 @@ public static function from(iterable $elements): JoinToString
 
     public function joinTo(string $separator): string
     {
-        return implode($separator, iterator_to_array($this->elements));
+        $result = '';
+        $first = true;
+
+        foreach ($this->elements as $element) {
+            if ($first) {
+                $result = $element;
+                $first = false;
+                continue;
+            }
+
+            $result .= sprintf('%s%s', $separator, $element);
+        }
+
+        return $result;
     }
 }
diff --git a/tests/Operations/Order/CollectionSortOperationTest.php b/tests/Operations/Order/CollectionSortOperationTest.php
index 11c3089..141e8d4 100644
--- a/tests/Operations/Order/CollectionSortOperationTest.php
+++ b/tests/Operations/Order/CollectionSortOperationTest.php
@@ -77,6 +77,29 @@ public function testSortDescendingByValue(iterable $elements, iterable $expected
         self::assertSame($expected, $actual->toArray());
     }
 
+    public function testSortDescendingByValueWithPredicate(): void
+    {
+        /** @Given a collection with unordered Amount objects */
+        $collection = Collection::createFrom(elements: [
+            new Amount(value: 100.50, currency: Currency::USD),
+            new Amount(value: 150.75, currency: Currency::EUR),
+            new Amount(value: 200.00, currency: Currency::USD)
+        ]);
+
+        /** @When sorting the collection in descending order by value with a custom predicate */
+        $actual = $collection->sort(
+            order: Order::DESCENDING_VALUE,
+            predicate: static fn(Amount $first, Amount $second): int => $first->value <=> $second->value
+        );
+
+        /** @Then the collection should be sorted by value in descending order */
+        self::assertSame([
+            2 => ['value' => 200.00, 'currency' => Currency::USD->name],
+            1 => ['value' => 150.75, 'currency' => Currency::EUR->name],
+            0 => ['value' => 100.50, 'currency' => Currency::USD->name]
+        ], $actual->toArray());
+    }
+
     public static function ascendingKeySortDataProvider(): iterable
     {
         yield 'Floats ascending by key' => [