Question About Undervolt

I have a Ryzen 5 5600X, and it really heats like crazy, around 80-90C on heavy gaming, and even 50C on idle on desktop without nothing running.

Buts that's because I use the default AMD cooler, and also my case is really bad too, only 2 frontal cooler etc...

Btw, I have applied both Undervolt and also fixed clock.

I'm using currently fixed 3.6Ghz with 1V, 3.6Ghz on all cores btw.

And this insanely improved my temps.

I tested around 30 minutes on cyberpunk, ultra graphics, and my 5600X went to max 65C, and around 40C on desktop.

But I have a question regarding this:

Is my setting of 3.6Ghz with 1V good? Which other settings do you recommend?

Does using both Undervolt and fixed clock will damage my CPU over time?

Is it safe to use this setting for long terms without damaging, or wearing down the CPU?

And also, I applied them by bios, but if I encounter any stability issues, freezing etc... can I access the bios and just reset everything? Or just remove the cmos battery?

Thanks in advance...