you begin with noob player when you achieved the level 10 you can chose different classe like warrior mage… and again when you achieve the level 10 to upgrade again with few new classes and for each new classes upgrade they have new skill and can use the old skill
in dev in unreal engines if possible to make like blueprint?
In unreal ebgine BPs is possible almost everything. This is possible too and its easy.
What do you need help? Because no one here will make full system for you…
Unlocking abilities is only simple math and some boolean branches…
Level + level… level 10? Set bool tree1unlock to true… and select ability.