80 Celsius is well within normal CPU temperature for an MBP.
If it is working too hard, then I would look at all those third-party software listed in the EtreCheck report, and make sure they are necessary and up-to-date. If not, uninstall them.
I would definitely get rid of the Western Digital helper software. Some versions caused major problems with some OS versions.
Do you need VideoGuard? Flash? Silverlight? (MS killed that years ago.)
Some versions of Chrome have been known to install Google software update agents that run wild with CPU resources.
You're also running some fan control program: might that be limiting the cooling? Try it without.
You've got Monolingual from 2014. Loads of other stuff that I have no idea what it is. 'Freedom' doesn't seem to have been updated by the developer since 2014.
Your Mac might also be slow because you're running out of disk storage.
I have a 2014 MBP, and just got a new battery from Apple, and it runs like a charm.