diff --git a/src/_pytest/config/__init__.py b/src/_pytest/config/__init__.py
index 49d63a357..1fd82f49d 100644
--- a/src/_pytest/config/__init__.py
+++ b/src/_pytest/config/__init__.py
@@ -638,9 +638,16 @@ class PytestPluginManager(PluginManager):
         if existing is not None:
             return cast(types.ModuleType, existing)
 
+        # conftest.py files there are not in a Python package all have module
+        # name "conftest", and thus conflict with each other. Clear the existing
+        # before loading the new one, otherwise the existing one will be
+        # returned from the module cache.
         pkgpath = resolve_package_path(conftestpath)
         if pkgpath is None:
-            _ensure_removed_sysmodule(conftestpath.stem)
+            try:
+                del sys.modules[conftestpath.stem]
+            except KeyError:
+                pass
 
         try:
             mod = import_path(conftestpath, mode=importmode, root=rootpath)
@@ -818,13 +825,6 @@ def _get_plugin_specs_as_list(
     )
 
 
-def _ensure_removed_sysmodule(modname: str) -> None:
-    try:
-        del sys.modules[modname]
-    except KeyError:
-        pass
-
-
 class Notset:
     def __repr__(self):
         return "<NOTSET>"
diff --git a/src/_pytest/fixtures.py b/src/_pytest/fixtures.py
index c184d2f3c..13c1790be 100644
--- a/src/_pytest/fixtures.py
+++ b/src/_pytest/fixtures.py
@@ -525,7 +525,7 @@ class FixtureRequest(abc.ABC):
         :param msg:
             An optional custom error message.
         """
-        raise self._fixturemanager.FixtureLookupError(None, self, msg)
+        raise FixtureLookupError(None, self, msg)
 
     def getfixturevalue(self, argname: str) -> Any:
         """Dynamically run a named fixture function.
@@ -970,7 +970,7 @@ class FixtureDef(Generic[FixtureValue]):
 
     def __init__(
         self,
-        fixturemanager: "FixtureManager",
+        config: Config,
         baseid: Optional[str],
         argname: str,
         func: "_FixtureFunc[FixtureValue]",
@@ -984,7 +984,6 @@ class FixtureDef(Generic[FixtureValue]):
         _ispytest: bool = False,
     ) -> None:
         check_ispytest(_ispytest)
-        self._fixturemanager = fixturemanager
         # The "base" node ID for the fixture.
         #
         # This is a node ID prefix. A fixture is only available to a node (e.g.
@@ -1010,7 +1009,7 @@ class FixtureDef(Generic[FixtureValue]):
         if scope is None:
             scope = Scope.Function
         elif callable(scope):
-            scope = _eval_scope_callable(scope, argname, fixturemanager.config)
+            scope = _eval_scope_callable(scope, argname, config)
         if isinstance(scope, str):
             scope = Scope.from_user(
                 scope, descr=f"Fixture '{func.__name__}'", where=baseid
@@ -1439,9 +1438,6 @@ class FixtureManager:
     by a lookup of their FuncFixtureInfo.
     """
 
-    FixtureLookupError = FixtureLookupError
-    FixtureLookupErrorRepr = FixtureLookupErrorRepr
-
     def __init__(self, session: "Session") -> None:
         self.session = session
         self.config: Config = session.config
@@ -1657,7 +1653,7 @@ class FixtureManager:
             Set this if this is a unittest fixture.
         """
         fixture_def = FixtureDef(
-            fixturemanager=self,
+            config=self.config,
             baseid=nodeid,
             argname=name,
             func=func,
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index aa134020f..36d2eba03 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -1323,7 +1323,7 @@ class Metafunc:
                 fixturedef = name2pseudofixturedef[argname]
             else:
                 fixturedef = FixtureDef(
-                    fixturemanager=self.definition.session._fixturemanager,
+                    config=self.config,
                     baseid="",
                     argname=argname,
                     func=get_direct_param_fixture_func,
diff --git a/src/_pytest/setuponly.py b/src/_pytest/setuponly.py
index 0f8be899a..0f1045806 100644
--- a/src/_pytest/setuponly.py
+++ b/src/_pytest/setuponly.py
@@ -47,20 +47,23 @@ def pytest_fixture_setup(
                 else:
                     param = request.param
                 fixturedef.cached_param = param  # type: ignore[attr-defined]
-            _show_fixture_action(fixturedef, "SETUP")
+            _show_fixture_action(fixturedef, request.config, "SETUP")
 
 
-def pytest_fixture_post_finalizer(fixturedef: FixtureDef[object]) -> None:
+def pytest_fixture_post_finalizer(
+    fixturedef: FixtureDef[object], request: SubRequest
+) -> None:
     if fixturedef.cached_result is not None:
-        config = fixturedef._fixturemanager.config
+        config = request.config
         if config.option.setupshow:
-            _show_fixture_action(fixturedef, "TEARDOWN")
+            _show_fixture_action(fixturedef, request.config, "TEARDOWN")
             if hasattr(fixturedef, "cached_param"):
                 del fixturedef.cached_param  # type: ignore[attr-defined]
 
 
-def _show_fixture_action(fixturedef: FixtureDef[object], msg: str) -> None:
-    config = fixturedef._fixturemanager.config
+def _show_fixture_action(
+    fixturedef: FixtureDef[object], config: Config, msg: str
+) -> None:
     capman = config.pluginmanager.getplugin("capturemanager")
     if capman:
         capman.suspend_global_capture()