There is a preferred side, but if you need juice, you can sit down in a coffee shop[1] you don't need to worry about it. Just make sure your main setup at home/ your office is correct.
[1] we'll be able to do that again sometime right?
Because I've had my MBP plugged in for the last 6 months, driving 2 external 4K displays on one side, power-in on the other, and an OWC 10Gigabit dock in the last port.
It's cool to touch, but I have the lid open (I use the LCD as the third display). I've read of people saying it gets hot when the lid is closed...
Nope, it's open; I use it as a second monitor as well. It's also on a stand (Roost) that exposes probably 99% of the bottom of the computer to air as well. 2019 Macbook Pro 16".
This is while the computer is under load (a Google Meet in Chrome, which is a power hungry little SOB). Also, the power is the only thing in the hot corner.
If it's always plugged in, then you're not charging the battery and there is less heat generated. I only have issues when it's charging the battery (maybe the battery controller is over there?)
Yeah, be careful with that - for some MacBook Pro models charging from the left side will cause overheating and CPU throttling issues.