Troubleshooting an overheating laptop

I’ve got an ASUS Zephyrus about a year out of warranty that has started to suddenly shutdown in any kind of gaming session over about 10 minute. No warnings or anything, just a power off shutdown.

What I’ve been able to gather from diagnostics:

1. Armory Crate shows at idle or low CPU, temps are about 50-60C. GPU temp at 0% is also similar.
2. When I run Cinebench for a CPU test, CPU temps very quickly spike to about 90+C.
3. When I stop Cinebench, CPU temps drop almost immediately. Like back down to the 50-60C range in seconds.
4. Fans are audibly revving up during tests or gaming. During Cinebench testing, fan RPMs were in the 4000s (though the visual bar was only half full?).

Any troubleshooting recommendations? I’m not opposed to taking apart the laptop to do some hands on fixes, this is more of a project laptop these days so I’m also trying to use this as a learning opportunity if it won’t be too difficult.