Contact Samsung Remote support Team before you reach Samsung Service Center for this issue.I am facing the same issue. Got my motherboard changed & even Samsung engineer visited home to check whether it is a fault with TV but no luck. They currently...

Many members has reported problem after software/security patch update. Please reach to Samsung Service Center for support. You can also reach Sam's Remote Support team from Members

remove the application permissions from Apps Manager to have a complete control

Default all mobile manufacturer from 2020 has LTE support. But check mobile features before buying.

@Sindhu2103 had you recently updated the latest security patch