"I have two brands of broken HDMI cables that I need to join to make them longer." (italics mine).
No, you don't need to join two cables. Nobody needs to do that, and I advise against it. Why? Several reasons:
mechanical robustness of the splice
signal integrity of the splice + shields (impedance mismatch, reflections, etc.)
added capacitance of ...
Aside from what Justme wrote (accept their answer, it's correct and the critical point here):
HDMI's data lines are really high-speed. That's easy to imagine: assume you have 1920×1200 px screen you want to feed at 60 fps. That makes 138.24 million pixels a second. Each of these have 8 bit on each color channel, and then there's 8b/10b-encoding, so that you ...
The signal on RCA Video output is called "composite video".
You can find "HDMI to composite video converters" online, with an HDMI input and a RCA output with composite video. If the product specification says "composite video output" it'll be the same signal that was on oldskool RCA video outputs, so that should work for your ...
This is just equalization of voltage between the two isolated and ungrounded (thus floating) switchmode power supplies in your TV and PC.
It is not dangerous, since the chassis exterior of the connector will always connect first on all connectors where this could cause damage.
Unless you own non-compliant cables or somehow manage to contact the pins before ...
Possibly this Abracon programmable MEMS oscillator with 40/80MHz outputs but the markings are not necessarily a match.
You could also try asking the manufacturer very nicely, or phoning them (harder to say no).
You will need an adapter or a connector to connect type-C USB and HDMI ports via an HDMI or adapter cable for charging the laptop. You can also charge the laptop by connecting the type-C port with the type-C port of your mobile phone using your data cable.