Clean hands are important:
MN66:12.2: He’d see a mendicant sitting in meditation in the cool shade, their hands and feet well washed after eating a delectable meal.
MN66:12.3: He’d think,
MN66:12.4: ‘The ascetic life is so very pleasant! The ascetic life is so very skillful!
But seriously, there's a wide diversity of hand positions throughout Buddhist traditions. For example, my Rinzai Zen teacher instructed us to grasp left thumb with right hand nestled in left hand. See also ruben2020's suggestions in the comments above.
Overall guiding principles would include refraining from dullness, drowsiness, and restlessness.
DN34:2.3.68: It’s when a mendicant has given up sensual desire, ill will, dullness and drowsiness, restlessness and remorse, and doubt.
In terms of positive attributes the Buddha instructs:
DN34:1.6.73: ‘This immersion is peaceful and sublime and tranquil and unified, not held in place by forceful suppression.’
From these clear instructions, one may infer that meditation hand positions should be relaxed without being slack. They should also be engaged without tension.
Notably, the subject of meditation is more important than the form:
DN34:1.6.96: But a meditation subject as a foundation of immersion is properly grasped, attended, borne in mind, and comprehended with wisdom.
DN34:1.6.97: That mendicant feels inspired by the meaning and the teaching in that Dhamma, no matter how a meditation subject as a foundation of immersion is properly grasped, attended, borne in mind, and comprehended with wisdom.
DN34:1.6.98: Feeling inspired, joy springs up. Being joyful, rapture springs up. When the mind is full of rapture, the body becomes tranquil. When the body is tranquil, one feels bliss. And when blissful, the mind becomes immersed.
DN34:1.6.99: This is the fifth opportunity for freedom.
Consult with your teacher for specifics of hand positions used in your chosen tradition.