I've grown in similar, it's difficult to mod things to block all light. Even when you spend time delicately adding foam tape or whatever there's always a crack lol.
Are you looking to block light for stealth or for flowering? If it's just for flowering your current cabinet will be fine as is, even with the janky seal. Thats not ideal so I'd suggest using a black shower curtain to hang over the door. Or maybe get in there and redo the seal. The shower curtain alone will get you golden tho.
Even if you still see light from the outside it's not strong enough going inside. You probably got 500w inside the cabinet blazing through cracks and 100w on the outside lighting the rest of the room. That 100w bulb in your ceiling ain't penetrating the cracks too well.
You don't have to block 100% of the light, it's just better when you get as close as you can. Plants need direct light to grow, enough light that wakes them up enough to grow. Cracks isn't enough light. Just don't be that guy with 100 pieces of electrical tape stuck to the inside of your tent. It's not that serious.