@Valentine created a simple design called Lepton (sadly no longer available, and impossible to manufacture anyway since the SE3082G mosfets no longer have the internal drain-source connection, and there are no substitutes), and I reworked it to be even simpler without a buck converter for my 12V powered robotic bird wing project where I need high power and small size/weight.
That got me accustomed to the essential components of BLDC drivers and the general process of PCB design (which to me feels like the ultimate puzzle game, trying to get all the signals where they need to go in minimal space by clever placement of each component and which MCU pins to use for which purpose). After burning two of them, I decided current sensors are also an essential component.
Then I watched a bunch of Robert Feranec videos on youtube and gained the ability to “see” electric fields when designing. High frequency energy (anything digital) travels in the dielectric rather than copper conductor, and if the outgoing and return conductors move apart from eachother, the field blooms outward to bridge the gap and will induce/be induced by any other fields in the same space. 4-layer PCBs with solid ground planes on the inner layers are like a cheat solution to the problem since the return current can travel directly underneath the outgoing line, 0.2mm away where the field remains very compact. But when a signal via goes between top and bottom layers, you also need a ground via nearby for the return current to travel to the other inner layer (“return current” is a misleading name, BTW. Both currents travel outward from the source together and meet up at the other end).
For debugging, my toolkit is a multimeter, oscilloscope, and cheap USB microscope (great for finding solder problems). I’d hold off on buying the oscilloscope until you encounter a problem you can’t solve without it. Make some small probes for use with the multimeter and oscilloscope. Solder pieces of ~0.8mm copper wire onto each end of a flexible silicone wire and sand one end to a slightly-blunted sharp point. Nickel plating would be nice; I have to to lightly sand the tip before use to remove oxide. The other end can be alligator clipped to the multimeter or hooked by the oscilloscope probe.