Sequential Blinkers

Hello everyone! I bought these sequential blinkers that run off an stm32 blue pill board. the only problem was that the boards were fried. this meant i had to install two new stm32 boards and code the blinkers myself. I came very far with the help of ChatGPT but now i'm stuck and it seems ChatGPT doesn't know how to help me any further. So can someone help me finish my project? it shouldn't be that difficult I think.

The issue i'm having:

i have two inputs: one that controls the blinkers when i use the turn signal (Pin B3). And one that controls the show mode where the leds do some kind of KITT style show (Pin A15).
now when i first turn on the blinker without using the switches it immediately starts blinking. of course i don't want this because i want it to respond to the switch.
Also, when i use the show mode switch it starts doing the led show sequence. but it does not stop till the whole sequence is done. And after the whole sequence is done it returns to blinking. it seems that the input for the blinkers does not work. I want the blinker switch to have priority over the show mode switch. I read somewhere that pin B3 only works if you disable JTAG but I can't find any more information about it.
One more thing i'm curious about is if the blinkers will respond correctly to the cars blinking sequence. the blinker will switch the input on and off and i don't know if the code can pick the signal up correctly.

I made the simulation in wokwi where the top button is for the show mode and the bottom button is for the blinker. Can someone please take a look at the code for me?
https://wokwi.com/projects/381912562866254849

Thank You for reading!