I Have the S20 5g [updated to today].
I successfully used the Bluetooth Tethering and Hotspot back in February. I have not changed carriers or plans. Now both do not work.
To be specific: when I attempt to swipe tethering for either Bluetooth/usb, the settings app crashes ("settings keeps stopping'' error message). I have Bluetooth enabled and am connected to another device.
For Hotspot, I receive the same error message as this other thread: https://us.community.samsung.com/t5/Galaxy-S-Phones/Mobile-Hotspot-not-working-on-Samsung-Galaxy-S20...
I followed the suggestions on rebooting, cache clearing, network settings reset, and trying it in safe mode.
What carrier are you on, and software version for you S20? (Settings > About Phone > Software Information > Build Number (last 4 characters)) It would help to know this info. This also seems like a reoccurring issue, try submitting an error report via the Samsung Members App so Samsung could help fix this right away! Thanks and good luck!