I ask him to give me access to digital lock,
Illegal to even ask
landlord does not have rights to property while tenant is renting.
He is correct.He can change the lock/or cylinder in the lock for his safety and should give you the key/code or original key only when he surrenders the property.
Perhaps something illegal is happening there. I rent a flat to someone and it would be a red flag if they did that.
Dont matter,he could be having a drug factory there,all the landlord can do is report his suspicion to the cops.And even if they cops find out that he is doing something illegal,the landlord still cannot do anything until the tenant is convicted of the crime,then too if he has mentioned that in the original umowa that no illegal activity should be conducted in the rented place(Usually no landlord in Poland is that brilliant to mention that clause esp in residentials).Even if any burst pipe or anything the fire/police or concerned dept should open the flat maybe with the landlords help but never the landlord by himself.
I hope the OP has the energy on his name as if the tenant dont pay,then the landlord should also not pay and let them cut off the utilities.Landlord can always pay the utilities after the problem is settled and reinstate the utilities.
I have my commercial Umowa in Poland of 57 pages and got a notary and a lawyer together and got it made and paid 1400pln same in US for 800$ from a real estate lawyer,except for anchor tenants who usually dictate there terms but they are corporate and never a problem.