Existential nihilism and metaphysical solipsism make for a bad combination. In fact they may even be mutually exclusive - I haven't quite made up my mind on that.
It's all well and good believing that my reality is the only true reality, and that other beings are merely representations of myself. That at least leaves one with a feeling of immense power and untouchability. But combine that with the belief that existence is pointless, without meaning, and you're (I'm) left with a rather redundant outlook. Further; the futility of searching for or assigning meaning being fully acknowledged, leaves one with little alternative but to sit and thumb-twiddle.
This is a brilliant quote from Donald A. Crosby (he's merely another representation of me, but it would be wrong not to let you (also me) know which (other) me came up with it): "There is no justification for life, but also no reason not to live. Those who claim to find meaning in their lives are either dishonest or deluded. In either case, they fail to face up to the harsh reality of the human situation".
Poor Dr Crosby is labouring under the misapprehension that he and others that are not me are real, separate beings, but apart from that he makes a good point: I exist and I may as well embrace that fact, because no other facts can be verified. I do celebrate the fact of my existence purely for that reason. It's all I can be sure of, so there's really nothing else to celebrate, ever. And I can only celebrate the knowledge, as opposed to making use of it or acting on it in some way, because it has no inherent worth or usefulness; it just is.
This is a philosophy of ever-decreasing circles, and I can begin to see why Descartes' (my) famous soundbite is perhaps the most well-known philosophical phrase there is. It's a deliberately pithy summation which just about perfectly describes the simplicity and brutality of existence.
It all sounds rather bleak, but actually it's just neutral, benign. Not that that's any better than bleak. It may even be worse.