This Unreal 5.3 Gameplay Ability System video is about putting the rest of the Upgrade System pieces together, and applying the Health Upgrade with the Character Blueprint.
We start by creating the Gameplay Effect for the Max Health Upgrade, and then build the Award Upgrade function in the Character Blueprint. Next, we ensure the Show Upgrades UI can only show up when there are Upgrade Points to spend, and hook up the Upgrade Button Widget to the Character Blueprint, and lastly show how to re-apply the Awarded Upgrades to the Character after transitioning to a different map.
https://dev.epicgames.com/community/learning/tutorials/9JDE/unreal-engine-36-player-progression-upgrade-system-max-health-let-s-make-a-top-down-shooter