diff --git a/src/libs/actions/PersonalDetails.ts b/src/libs/actions/PersonalDetails.ts
index 066ec96db9ad..01f8c2f4916b 100644
--- a/src/libs/actions/PersonalDetails.ts
+++ b/src/libs/actions/PersonalDetails.ts
@@ -55,6 +55,7 @@ function getDisplayName(login: string, personalDetail: Pick<PersonalDetails, 'fi
     const lastName = userDetails.lastName ?? '';
     const fullName = `${firstName} ${lastName}`.trim();
 
+    // It's possible for fullName to be empty string, so we must use "||" to fallback to userLogin.
     return fullName || userLogin;
 }
 
@@ -70,11 +71,17 @@ function getDisplayNameForTypingIndicator(userAccountIDOrLogin: string, defaultD
     // so Number(string) is NaN. Search for personalDetails by login to get the display name.
     if (Number.isNaN(accountID)) {
         const detailsByLogin = Object.entries(allPersonalDetails ?? {}).find(([, value]) => value?.login === userAccountIDOrLogin)?.[1];
-        return detailsByLogin?.displayName ?? userAccountIDOrLogin;
+
+        // It's possible for displayName to be empty string, so we must use "||" to fallback to userAccountIDOrLogin.
+        // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
+        return detailsByLogin?.displayName || userAccountIDOrLogin;
     }
 
     const detailsByAccountID = allPersonalDetails?.[accountID];
-    return detailsByAccountID?.displayName ?? detailsByAccountID?.login ?? defaultDisplayName;
+
+    // It's possible for displayName to be empty string, so we must use "||" to fallback to login or defaultDisplayName.
+    // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
+    return detailsByAccountID?.displayName || detailsByAccountID?.login || defaultDisplayName;
 }
 
 /**
@@ -83,7 +90,9 @@ function getDisplayNameForTypingIndicator(userAccountIDOrLogin: string, defaultD
  * so we return empty strings instead.
  */
 function extractFirstAndLastNameFromAvailableDetails({login, displayName, firstName, lastName}: PersonalDetails): FirstAndLastName {
-    if (firstName ?? lastName) {
+    // It's possible for firstName to be empty string, so we must use "||" to consider lastName instead.
+    // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
+    if (firstName || lastName) {
         return {firstName: firstName ?? '', lastName: lastName ?? ''};
     }
     if (login && Str.removeSMSDomain(login) === displayName) {
diff --git a/src/types/onyx/index.ts b/src/types/onyx/index.ts
index 683292327727..f02d3d2f548f 100644
--- a/src/types/onyx/index.ts
+++ b/src/types/onyx/index.ts
@@ -51,59 +51,59 @@ import WalletTransfer from './WalletTransfer';
 
 export type {
     Account,
-    Request,
+    AccountData,
+    AddDebitCardForm,
+    BankAccount,
+    Beta,
+    BlockedFromConcierge,
+    Card,
     Credentials,
+    Currency,
+    CustomStatusDraft,
+    DateOfBirthForm,
+    Download,
+    Form,
+    FrequentlyUsedEmoji,
+    Fund,
     IOU,
+    Login,
+    MapboxAccessToken,
     Modal,
     Network,
-    CustomStatusDraft,
+    OnyxUpdateEvent,
+    OnyxUpdatesFromServer,
+    PersonalBankAccount,
     PersonalDetails,
-    PrivatePersonalDetails,
-    Task,
-    Currency,
-    ScreenShareRequest,
-    User,
-    Login,
-    Session,
-    Beta,
-    BlockedFromConcierge,
     PlaidData,
-    UserWallet,
-    WalletOnfido,
-    WalletAdditionalDetails,
-    WalletTerms,
-    BankAccount,
-    Card,
-    Fund,
-    WalletStatement,
-    PersonalBankAccount,
-    ReimbursementAccount,
-    ReimbursementAccountDraft,
-    FrequentlyUsedEmoji,
-    WalletTransfer,
-    MapboxAccessToken,
-    Download,
-    PolicyMember,
     Policy,
     PolicyCategory,
+    PolicyMember,
+    PolicyMembers,
+    PolicyTag,
+    PolicyTags,
+    PrivatePersonalDetails,
+    RecentlyUsedCategories,
+    RecentlyUsedTags,
+    RecentWaypoint,
+    ReimbursementAccount,
+    ReimbursementAccountDraft,
     Report,
-    ReportMetadata,
     ReportAction,
+    ReportActionReactions,
     ReportActions,
     ReportActionsDrafts,
-    ReportActionReactions,
+    ReportMetadata,
+    Request,
+    ScreenShareRequest,
     SecurityGroup,
+    Session,
+    Task,
     Transaction,
-    Form,
-    AddDebitCardForm,
-    DateOfBirthForm,
-    OnyxUpdatesFromServer,
-    RecentWaypoint,
-    OnyxUpdateEvent,
-    RecentlyUsedCategories,
-    RecentlyUsedTags,
-    PolicyTag,
-    PolicyTags,
-    PolicyMembers,
-    AccountData,
+    User,
+    UserWallet,
+    WalletAdditionalDetails,
+    WalletOnfido,
+    WalletStatement,
+    WalletTerms,
+    WalletTransfer,
 };