diff --git a/arrow/factory.py b/arrow/factory.py
index 0913bfe1..eaa8d7cf 100644
--- a/arrow/factory.py
+++ b/arrow/factory.py
@@ -189,6 +189,7 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
         arg_count = len(args)
         locale = kwargs.pop("locale", DEFAULT_LOCALE)
         tz = kwargs.get("tzinfo", None)
+        has_tzinfo_kwarg = "tzinfo" in kwargs
         normalize_whitespace = kwargs.pop("normalize_whitespace", False)
 
         # if kwargs given, send to constructor unless only tzinfo provided
@@ -196,7 +197,7 @@ def get(self, *args: Any, **kwargs: Any) -> Arrow:
             arg_count = 3
 
         # tzinfo kwarg is not provided
-        if len(kwargs) == 1 and tz is None:
+        if len(kwargs) == 1 and not has_tzinfo_kwarg:
             arg_count = 3
 
         # () -> now, @ tzinfo or utc
diff --git a/arrow/parser.py b/arrow/parser.py
index fc3774b0..ce618b5d 100644
--- a/arrow/parser.py
+++ b/arrow/parser.py
@@ -166,7 +166,7 @@ class DateTimeParser:
     _TZ_NAME_RE: ClassVar[Pattern[str]] = re.compile(r"\w[\w+\-/]+")
     # NOTE: timestamps cannot be parsed from natural language strings (by removing the ^...$) because it will
     # break cases like "15 Jul 2000" and a format list (see issue #447)
-    _TIMESTAMP_RE: ClassVar[Pattern[str]] = re.compile(r"^\-?\d+\.?\d+$")
+    _TIMESTAMP_RE: ClassVar[Pattern[str]] = re.compile(r"^[-+]?\d+(?:\.\d+)?$")
     _TIMESTAMP_EXPANDED_RE: ClassVar[Pattern[str]] = re.compile(r"^\-?\d+$")
     _TIME_RE: ClassVar[Pattern[str]] = re.compile(
         r"^(\d{2})(?:\:?(\d{2}))?(?:\:?(\d{2}))?(?:([\.\,])(\d+))?$"
@@ -725,7 +725,7 @@ def _build_datetime(parts: _Parts) -> datetime:
         timestamp = parts.get("timestamp")
 
         if timestamp is not None:
-            return datetime.fromtimestamp(timestamp, tz=timezone.utc)
+            return datetime.fromtimestamp(float(timestamp), tz=timezone.utc)
 
         expanded_timestamp = parts.get("expanded_timestamp")
 
diff --git a/tests/test_factory.py b/tests/test_factory.py
index 056cee41..1942cb65 100644
--- a/tests/test_factory.py
+++ b/tests/test_factory.py
@@ -137,6 +137,12 @@ def test_kwarg_tzinfo(self):
             self.factory.get(tzinfo=ZoneInfo("US/Pacific")), self.expected
         )
 
+    def test_kwarg_tzinfo_none(self):
+        assert_datetime_equality(
+            self.factory.get(tzinfo=None),
+            datetime.now(timezone.utc).replace(tzinfo=timezone.utc),
+        )
+
     def test_kwarg_tzinfo_string(self):
         self.expected = (
             datetime.now(timezone.utc)
@@ -287,6 +293,11 @@ def test_two_args_str_str(self):
 
         assert result._datetime == datetime(2013, 1, 1, tzinfo=tz.tzutc())
 
+    def test_two_args_str_str_tzinfo_none(self):
+        result = self.factory.get("2013-01-01", "YYYY-MM-DD", tzinfo=None)
+
+        assert result._datetime == datetime(2013, 1, 1, tzinfo=tz.tzutc())
+
     def test_two_args_str_tzinfo(self):
         result = self.factory.get("2013-01-01", tzinfo=ZoneInfo("US/Pacific"))