Hi
Had high idle temps like you. If you have multiple displays, check your gpu clock in precision when idle. It should be at more or less 240 mHz. If it's not, it's because GPU doesn't underclock when idle as it should. It's a known bug from Nvidia gpus/drivers with multiple displays.
I have two screens on display port and my TV on HDMI. If I unplug my TV, my GPU clock is OK at 240mhz. If it is plugged -> more or less 900 mhZ -> temps go up until fans start spinning at 60°C.
Try to use NVIDIA Inspector Multi display Power Saver if you are in this case, boom problem solved. With this my temps are at 39°C when idle with FANS OFF.
Hope it'll help