OK there are two things you have to realise. Firstly, the idea that you must be gifted your first tarot deck is actually a superstition put about by charlatans who don’t want it widely known that if anybody can learn the tarot, they would be out of a job! It is “gatekeeping” at its worst. Do not let anyone shame you into not buying a new tarot deck, you are free to do so if you want.
However: the second thing to realise is that there is another option which you haven’t yet considered, i.e. that of getting your first tarot deck back. If it has truly become yours then this is what I (if I were in your position) would be first considering. My personal inclination would be to go to my favourite spirit of the Goetia, Andromalius, who is exceptionally good at recovering stolen items, although if you have any feelings left for the person who stole your tarot deck, you would have to word your petition to the spirit very carefully.
Alex Sumner’s answer to What happens when the gifter of my first tarot deck stole it back out of anger? Can I still buy my second deck? I was super attached and they were working for me.