Yaarel
🇮🇱 🇺🇦 He-Mage
I havent seen your Psychic, so I cant comment on it.As shown with my Psychic, you can do both, or at least I think you can in a satisfying way. Psi Points on invocation-like features, which you can easily expand, and then spell slots to keep with the current system. Its a bit different, ya, but it achieves the goal IMO.
But generally, I disfavor spell points. I dislike Sorcerer spell points which are a needless complexity. In 3e, I loved the psi points, because they were so much better than vancian casting.
But now in 5e, the now-normal spontaneous casting is better than both vancian and spell points. Its simplicity and effectiveness are ideal.
5e Warlock spellcasting is satisfying. The powerful at-wills are perfect. The normal slots refresh after an exertion. And the highest slot arcanums are like novas.