This is a topic that needs to come up more often than not. Summer heat anywhere in the world is detrimental to computer hardware. I run my PC with the case side open. This keeps my blisteringly hot i9-12900K and RTX3080 cool within "safe working conditions". Operating the computer with the case side on, sent my video card right into thermal-throttling because the only air vent on the case was a segment with holes in it where the video card is located. The CPU is water cooled and that gets vented out the back so there were no problems with that.
I agree that running temperature and system monitoring tools can impact performance even though I do use HW Monitor Pro. I use that to periodically check that everything is running where it should and do so manually, however, I do use MSI Afterburner for my video card. I set the curve to an automatic but using my own temperature curve. By doing this, I can keep the video card temps down to about 65 C when using Trainz. This doesn't appear to impact any performance.
Keeping the interior of a PC clean is a given no matter what time of year it is. Using a rocket squeeze-bulb to blow the air out is a lot less expensive than canned air and I highly recommend those now. Remember to put something into the fans to prevent them from spinning too quickly when the air is blown through them to remove the dust. In addition to the Rocket to get the dirt out of the hard-to-reach places, I also use a Hippo vacuum. This is a special vacuum cleaner designed for cleaning computer equipment. Unlike a home vacuum, this one is grounded and doesn't produce any errant static electricity to zap the computer components. This vacuum can also work as a blower and I do that to blow out the dust from inside the case before using the Rocket to get to the crevices where the Hippo blowing the dust can't reach, and after blowing out the video card, I have noticed a substantial drop in temperatures.
There is one more thing that needs to be mentioned in addition to heat. During the warmer months, we also deal with lower power due to more people using air-conditioning. This lower power can affect the operation due to the components working harder and drawing more current from the power supply. To prevent this damage, in addition to that caused by spikes and brown outs, it's highly recommended if not mandatory to use a UPS. A UPS such as a Tripp-Lite, rated for the computer plus the display, will not only prevent spikes and burnouts from affecting the components but also will allow the computer to be shut down properly with time to save and shut down rather than suddenly turning off.