I'd suggest a new topic since it's likely not related to the beta build.
Then flash a new rom (Xiaomi stock, Lineage etc.) to see if it persists, but it's likely a hardware failure if even the HW test app doesn't work.
I've quit the WhatsApp beta program, it has way too many issues lately while Whatsapp is a vital app for me.
They used to roll out new features in the beta channel before but now it's just a public beta with breaking bugs.
It's likely a permissions issue, they need exact location to scan for nearby wifi.
Also apps need to support it, outdated apps that aren't updated for Android 13 won't work.
I don't think the F3 it's screen supports dynamic refresh rate.
It going to from 120 to 60 in for example YouTube app is not an example of dynamic refresh rate I guess.
For me Kimovil is reliable:
https://www.kimovil.com/en/where-to-buy-xiaomi-redmi-k60-8gb-256gb-cn
I don't think your problems are related to thst though. The loss of 4g bands would lead to for example bad 4g coverage inside buildings, not GSM/SMS issues.
See:
https://xiaomi.eu/community/threads/notification-issues-in-miui-14.68157/
Workaround is to use the weekly Dev rom, it doesn't have the notification issue.
You can flash it without wipe from stable.