diff --git a/packages/edit-post/src/components/layout/index.js b/packages/edit-post/src/components/layout/index.js
index ab8c393b8172f4..84220f37cf7e0e 100644
--- a/packages/edit-post/src/components/layout/index.js
+++ b/packages/edit-post/src/components/layout/index.js
@@ -417,6 +417,7 @@ function Layout( {
 		hasHistory,
 		isWelcomeGuideVisible,
 		templateId,
+		isDevicePreview,
 	} = useSelect(
 		( select ) => {
 			const { get } = select( preferencesStore );
@@ -424,6 +425,8 @@ function Layout( {
 				select( editPostStore )
 			);
 			const { canUser, getPostType } = select( coreStore );
+			const { getDeviceType, getEditorMode, getRenderingMode } =
+				select( editorStore );
 
 			const supportsTemplateMode = settings.supportsTemplateMode;
 			const isViewable =
@@ -434,7 +437,7 @@ function Layout( {
 			} );
 
 			return {
-				mode: select( editorStore ).getEditorMode(),
+				mode: getEditorMode(),
 				isFullscreenActive:
 					select( editPostStore ).isFeatureActive( 'fullscreenMode' ),
 				hasActiveMetaboxes: select( editPostStore ).hasMetaBoxes(),
@@ -444,7 +447,7 @@ function Layout( {
 				isDistractionFree: get( 'core', 'distractionFree' ),
 				showMetaBoxes:
 					! DESIGN_POST_TYPES.includes( currentPostType ) &&
-					select( editorStore ).getRenderingMode() === 'post-only',
+					getRenderingMode() === 'post-only',
 				isWelcomeGuideVisible: isFeatureActive( 'welcomeGuide' ),
 				templateId:
 					supportsTemplateMode &&
@@ -453,6 +456,7 @@ function Layout( {
 					! isEditingTemplate
 						? getEditedPostTemplateId()
 						: null,
+				isDevicePreview: getDeviceType() !== 'Desktop',
 			};
 		},
 		[ currentPostType, isEditingTemplate, settings.supportsTemplateMode ]
@@ -594,7 +598,11 @@ function Layout( {
 						extraContent={
 							! isDistractionFree &&
 							showMetaBoxes && (
-								<MetaBoxesMain isLegacy={ ! shouldIframe } />
+								<MetaBoxesMain
+									isLegacy={
+										! shouldIframe || isDevicePreview
+									}
+								/>
 							)
 						}
 					>
diff --git a/packages/edit-post/src/components/layout/style.scss b/packages/edit-post/src/components/layout/style.scss
index 18f12c1dbfbb92..aa839f9171c08d 100644
--- a/packages/edit-post/src/components/layout/style.scss
+++ b/packages/edit-post/src/components/layout/style.scss
@@ -106,12 +106,15 @@
 	clear: both;
 }
 
-.has-metaboxes .editor-visual-editor {
-	flex: 1;
+// Only when the split view is active the visual editor should allow shrinking and
+// its main size should be zero.
+.has-metaboxes .interface-interface-skeleton__content:has(.edit-post-meta-boxes-main) .editor-visual-editor {
+	flex-shrink: 1;
+	flex-basis: 0%;
+}
 
-	&.is-iframed {
-		isolation: isolate;
-	}
+.has-metaboxes .editor-visual-editor.is-iframed {
+	isolation: isolate;
 }
 
 // Adjust the position of the notices