The virus hijacks existing cellular mechanisms for its own purposes. Interfering with those mechanisms could halt the replication of the virus, but it could also kill you. As an example, the virus enters cells through the use of the ACE2 protein. That protein plays a part in regulating blood pressure, so you can imagine the danger that could come from doing playing around with that.
However, SARS-CoV-2 is an RNA virus and its genome codes for an RNA polymerase enzyme that copies its RNA genome. Human cells do not use RNA polymerase and so it could be a target for a drug. This is how remdesivir works, but you have to find a compound that can effectively interfere, but that isn't too incidentally toxic to humans.
> I suddenly got an urge to learn how I can program proteins to do the stuff I want to do. From reading material around proteins, it seems they are nothing more than mechanical devices.
Good luck, I'd argue that our ability to design functional, non-trivial proteins de novo is essentially non-existent. The function of a protein is highly dependent of its shape and the process of how a string of amino acids folds into the final shape of the protein is extremely complicated and requires supercomputers to simulate. Not to mention that proteins may require help from another proteins to properly fold. Proteins may also be modified after they have folded and a lot of proteins require things like metal ions or other cofactors to actually be functional.