FallSouls is a mod by kassent which stops the game from being paused while the player is using menus. It is mostly compatible with Horizon, with the exception of a visual bug affecting the Hunter and Future Soldier perk icons and that the death system does not function if the player dies while in the Pip-Boy menu. However, it has a number of issues unrelated to compatibility, such as making it impossible to read holotapes while in power armor.
It also has a minor compatibility issue with Sim Settlements: when using the Town Meeting Gavel to gather your settlers, instead of waiting for you to close your pip-boy the screen will go dark immediately and seemingly get stuck. In order to fix this, simply press your Pip-Boy key to put the menu away, and the transition will load as normal.