diff --git a/services/fxaccounts/FxAccountsStorage.sys.mjs b/services/fxaccounts/FxAccountsStorage.sys.mjs
--- a/services/fxaccounts/FxAccountsStorage.sys.mjs
+++ b/services/fxaccounts/FxAccountsStorage.sys.mjs
@@ -560,11 +560,11 @@
         FXA_PWDMGR_REALM
       );
       if (existingLogins.length) {
         Services.logins.modifyLogin(existingLogins[0], login);
       } else {
-        await Services.logins.addLoginAsync(login);
+        Services.logins.addLogin(login);
       }
       log.trace("finished write of user data to the login manager");
     } catch (ex) {
       if (ex instanceof this.STORAGE_LOCKED) {
         throw ex;
diff --git a/services/sync/modules/engines/passwords.sys.mjs b/services/sync/modules/engines/passwords.sys.mjs
--- a/services/sync/modules/engines/passwords.sys.mjs
+++ b/services/sync/modules/engines/passwords.sys.mjs
@@ -344,11 +344,11 @@
         JSON.stringify(login.httpRealm) +
         "; " +
         "formSubmitURL: " +
         JSON.stringify(login.formActionOrigin)
     );
-    await Services.logins.addLoginAsync(login);
+    Services.logins.addLogin(login);
   },
 
   async remove(record) {
     this._log.trace("Removing login " + record.id);
 
diff --git a/services/sync/tps/extensions/tps/resource/modules/passwords.sys.mjs b/services/sync/tps/extensions/tps/resource/modules/passwords.sys.mjs
--- a/services/sync/tps/extensions/tps/resource/modules/passwords.sys.mjs
+++ b/services/sync/tps/extensions/tps/resource/modules/passwords.sys.mjs
@@ -97,11 +97,10 @@
       this.props.username,
       this.props.password,
       this.props.usernameField,
       this.props.passwordField
     );
-    // TODO: use `addLoginAsync` instead, see https://bugzilla.mozilla.org/show_bug.cgi?id=1829396
     Services.logins.addLogin(login);
     login.QueryInterface(Ci.nsILoginMetaInfo);
     return login.guid;
   },
 
diff --git a/toolkit/components/passwordmgr/LoginManagerParent.sys.mjs b/toolkit/components/passwordmgr/LoginManagerParent.sys.mjs
--- a/toolkit/components/passwordmgr/LoginManagerParent.sys.mjs
+++ b/toolkit/components/passwordmgr/LoginManagerParent.sys.mjs
@@ -1412,13 +1412,11 @@
         // Update `existingLogin` with the new password if modifyLogin didn't
         // throw so that the prompts later uses the new password.
         existingLogin.password = formLogin.password;
       } else if (!autoSavedLogin) {
         lazy.log("Auto-saving new login with empty username.");
-        existingLogin = await Services.logins.addLoginAsync(
-          formLoginWithoutUsername
-        );
+        existingLogin = Services.logins.addLogin(formLoginWithoutUsername);
         // Remember the GUID where we saved the generated password so we can update
         // the login if the user later edits the generated password.
         generatedPW.storageGUID = existingLogin.guid;
         notifySaved = true;
       }