The outside of the Switch is definitely exhausting more heat, which could suggest more heat is being taken away from the SOC and consequently cooling it down.
Dumb hypothesizes from a non-expert:
You have cleaned dust during your modifications, making a better air Flow (more heat out, better internal thermal, better CPU performance).
You have broken a thermal sensor and your switch is actually heating a lot while the sensor think it does not.
This afternoon, a friend brings its Switch with Mario Kart (she have the DLC on this Switch and another Switch at home) and had some message about update and shared DLC.
We actually could not play the DLC because the second Switch on its home was not uptodate and online.
Dunno what it means, but I suspect you could have some surprise if you have no access to your other Switch.
Yes, they previously hire a private detective for Switch emulator dev few years ago and did some intimidation. It’s illegal to do this (at least in EU). A company should use law, whatever reason it is.
Years ago, controllers where almost unbreakable. Look at where we are now.