For all baudrate-related situations, you should send some data and verify the baudrate using an oscilloscope. Then you would quickly notice if you have misscalculated something.

Just trying to debug the receiver means you will not know if it's a baudrate issue, an interrupt handler issue or something else if you fail to receive data. Always look at your source code lines and make yourself this question: "what part of this code can I prove? And how do I prove it?"

After a while, you will be better and better writing testable code. So you will spend less and less time debugging, because your errors will be caught that much quicker. But it's important to try to debug the small LEGO pieces one-by-one instead of combining 1000 pieces and then start to debug the complex system. There will be too many unknowns, making it very, very hard to figure out why something fails if you start directly with system testing before having done all possible module testing.