Prior choice for discrete features - logistic regression

I don’t see any obvious problems in this model, which made me think I’m not sure I understand the issue you’re having: does the model have problem sampling?

I’m note sure I understand how to use binomial regression for this application, and I can’t really think on how to implement the n trials idea in my specific problem

The Bernoulli is just a special case of the Binomial, where n_trials = 1.

I have little samples and almost 2k predictors

What do you mean by that? Your X matrix has 2k columns?

The model I did so far below, usually with mu_beta = 0, sigma = 1 and constant = 0

Setting constant = 0 means your model doesn’t haven’t an intercept (i.e baseline), which is rare. Any reason you’re doing that here?