you need a better cooling / airflow solution. if your temps are going above 75c you're doing something wrong (or you live in a yurt in the desert.)

at some point you will need to upgrade. the operation life of a CPU is around 10 years. HDD / SSDs have an average lifespan of about 3-10 years depending on luck and use case.

Motherboards have capacitor that wear out / leak.. parts need to be replaced.

I recommend budgeting toward an component upgrade every 2 years. and a full replacement / system overhaul every 5/6 years.

you're lucky, the upgrade cycle used to be far shorter because tech was still racing toward the limits of silicon. now were in a place where node shrinks and architecture improvements are the thing driving progress.