Yes, lowering voltage lowers power consumption and hence lowers temps and noise.
Which way are each of your case fans facing? Sounds like you've got an airflow direction issue. More fans doesn't always decrease temps, but it certainly should never make them INCREASE.
I have a Chiptronex Raptor RGB Case
flipkart.com/chiptronex-raptor-rgb-tempered-glass-atx-gaming-cabinet-without-smps/p/itmfaf9rgczmxsnb
View: https://www.youtube.com/watch?v=T8I2nv2W2ps
This is how it looks
It came with 3 Front intake and and 1 rear exhaust I had added 3 Static RGB 120MM fans(Random ones form Aliexpress it says 50CFM) on top
I have a Snowman M-T6 mounted on a i5-4590 in an orientation where the fans pull air from bottom to top because my Mobo(Biostar H81MHV3) wont allow me to fit it left to right RAM clearance issue also fitted the rear exhaust outside the case and flipped it and using it as intake due to the same clearance issue the case do not have enough space to fit the fan inside after using the cooler
so I have 1 rear sending air to the CPU Cooler
3x front intake
3x top exhaust
all 120mm fans
the top exhaust all 3 are always running and I have a button to turn on or off the rear and front fans so when I turn them off the GPU temps decrease(runs cooler by 3-4C) and when I turn on the front 3 intake and rear 1 intake GPU temps increase(runs 3-4C hotter) I have no idea why and what to do I also stuck a stick and stopped the rear intake and let only the 3x front intake and 3x top exhaust run and I still got the same problem but with a small change the GPU temps raised by only 2-3C
So running the read intake increase GPU temp by 1-2C and runing the 3x front intake increases the temps by 1-2C
My ambient room temp is 32C i live in Pondicherry sount east India the city is mostly hot all the time
Also my HDD temps alo goes to 46-47C when GPU load is high during idle HDD temp is 38C.
Also the case says it supports 320mm rad on top and front but it cant fit any radiator anywhere because this stupid case do not have enough clearance between the mobo and the top (even the top exhaust fans are almost touching the mobo) and also the screw holes and the space(width of the case) do not seem to fit any AIO the space is very less.
The pics of my PC are in the below links
*Pics are taken with side panel off but I always leave the side glass panel on and all the info shared above are the temps with side panel on.
https://drive.google.com/uc?id=1ku_ZVJucMJ6vzrYpxx7YQYfm5wkRf-Qd
https://drive.google.com/uc?id=1wfPFKCzIW9GrB5nZMxcF6HlUW0Tti6qM
https://drive.google.com/uc?id=1DIiPG2HhWAMBQR0wrUDJLa_QWq0QGdKn
https://drive.google.com/uc?id=1mtCi_DrZIzwDV2xkWReRttzJn-7W_QM2
Access Google Drive with a Google account (for personal use) or Google Workspace account (for business use).
drive.google.com
https://drive.google.com/uc?id=1savQ7029i4Yqd7sgPII8hlYksiJPc1Q1
https://drive.google.com/uc?id=12AlRJLCZp1ncLbRvc15cOTuULB4aOy0q