That depends on the specific TLS setup. Badly configured TLS 1.2 would allow downgrade attacks, TLS 1.3 would not. I highly doubt the “in most circumstances” line, my guess would be that at least the big ones like gmail don’t allow unsecured communication with their servers at all. If not for their users’s privacy, then at least to combat spam.
That depends on the specific TLS setup. Badly configured TLS 1.2 would allow downgrade attacks, TLS 1.3 would not. I highly doubt the “in most circumstances” line, my guess would be that at least the big ones like gmail don’t allow unsecured communication with their servers at all. If not for their users’s privacy, then at least to combat spam.