I'll just give up and stop experimenting
Experimenting is to advance and improve knowledge.
The functions and interactions of every part of a circuit such as that can be predicted without building it, if you understand electronics.
The people who "invent" circuits like that
do not understand the most basic principles.
One very obviously stupid part is having a bridge rectifier in a point where the voltage is already rectified and smoothed.
A less obvious one to someone not familiar with electronics is the "voltage divider" to reduce a supposed 5000V or more to 12V...
300W in to the "12V to 120V inverter" at the output requires 300/12 = 25 Amps input current, not allowing for inefficiencies.
The tesla coil output will be milliamps if you are lucky.
If you
could connect a power source capable of 25A at 5000V, the upper resistor in the "voltage divider" would be dissipating around 125,000 Watts as heat; for 300W output.
The whole circuit and concept is simply nonsense, parts connected virtually at random.
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If you were considering building something with reasonably low cost and low danger, I'd say go ahead regardless, as testing and examining whatever you built (whether it works or not) adds to your knowledge and understanding.
However the thing you are considering will cost ludicrous amounts and is very dangerous, with voltages involved that that you cannot test and examine with such as a multimeter. It's a waste of money and you cannot examine the details of what it is doing safely or without extremely expensive and specialised test equipment.