diff --git a/roles/custom/matrix-bot-draupnir/tasks/validate_config.yml b/roles/custom/matrix-bot-draupnir/tasks/validate_config.yml
index c5816ea51..e40178cef 100644
--- a/roles/custom/matrix-bot-draupnir/tasks/validate_config.yml
+++ b/roles/custom/matrix-bot-draupnir/tasks/validate_config.yml
@@ -45,9 +45,17 @@
   with_items:
     - {'name': 'matrix_bot_draupnir_config_accessToken', when: "{{ matrix_bot_draupnir_pantalaimon_use }}"}
     - {'name': 'matrix_bot_draupnir_config_accessToken', when: "{{ matrix_bot_draupnir_login_native }}"}
-    - {'name': 'matrix_bot_draupnir_pantalaimon_use', when: "{{  matrix_bot_draupnir_config_experimentalRustCrypto }}"}
   when: "item.when | bool and not (vars[item.name] == '' or vars[item.name] is none)"
 
+- name: Fail when matrix_bot_draupnir_config_experimentalRustCrypto is enabled together with matrix_bot_draupnir_pantalaimon_use
+  ansible.builtin.fail:
+    msg: >-
+      Your configuration is trying to enable matrix_bot_draupnir_config_experimentalRustCrypto and matrix_bot_draupnir_pantalaimon_use at the same time.
+      These settings are mutually incompatible and therefore cant be used at the same time.
+  when:
+    - matrix_bot_draupnir_pantalaimon_use
+    - matrix_bot_draupnir_config_experimentalRustCrypto
+
 - when: "matrix_bot_draupnir_pantalaimon_use == 'true' and matrix_bot_draupnir_pantalaimon_breakage_ignore == 'false'"
   block:
     - name: Inject warning if Pantalaimon is used together with Draupnir
diff --git a/roles/custom/matrix-synapse/defaults/main.yml b/roles/custom/matrix-synapse/defaults/main.yml
index 0aa9d5f4b..23c08241c 100644
--- a/roles/custom/matrix-synapse/defaults/main.yml
+++ b/roles/custom/matrix-synapse/defaults/main.yml
@@ -468,6 +468,13 @@ matrix_synapse_rc_federation:
 
 matrix_synapse_federation_rr_transactions_per_room_per_second: 50
 
+# Controls the rate limit for delayed event management.
+#
+# This is only applied if `matrix_synapse_experimental_features_msc4140_enabled` is set to `true`.
+matrix_synapse_rc_delayed_event_mgmt:
+  per_second: 1
+  burst_count: 20
+
 # Controls the templates directory setting.
 #
 # See:
@@ -1265,7 +1272,9 @@ matrix_synapse_experimental_features_msc3266_enabled: true
 # Delayed events are required for proper call (Element Call) participation signalling.
 # If disabled it is very likely that you end up with stuck calls in Matrix rooms.
 #
-# Related to `matrix_synapse_max_event_delay_duration`
+# Related to:
+# - `matrix_synapse_max_event_delay_duration`
+# - `matrix_synapse_rc_delayed_event_mgmt`
 #
 # See https://github.com/matrix-org/matrix-spec-proposals/pull/4140
 matrix_synapse_experimental_features_msc4140_enabled: false
diff --git a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2 b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
index 218be3b03..bd76b5e14 100644
--- a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
+++ b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
@@ -2999,6 +2999,7 @@ experimental_features:
 
 {% if matrix_synapse_experimental_features_msc4140_enabled %}
 max_event_delay_duration: {{ matrix_synapse_max_event_delay_duration | to_json }}
+rc_delayed_event_mgmt: {{ matrix_synapse_rc_delayed_event_mgmt | to_json }}
 {% endif %}
 
 # vim:ft=yaml