That’s a FANTASTIC machine!
The big problem with popping a new CPU in is how slow all the other stuff on your mobo is. Your old mobo maybe has one m.2 port? Might even be SATA m.2? We never used it on the 4670k machine. Also RAM speeds, if you could pop a 13900k in there, it’d be right crippled by DDR3. Always new mobo with new CPU for me. Also because I upgrade my CPU every 7-9 years, and stuff changes insanely. My partner’s mobo has FOUR GOSH DANG m.2 SLOTS. FOUR! We almost went SATA-less but had an unopened 4TB HDD so we popped that in there.