"The bread is hot."
That is not actually true. You may say パンは熱いです and not refer to all bread; it's the distinction between setting パン as topic or remaining with the current one, which may be something like あの店には "in that shop" or something similar. Setting パン as the topic may equally mean "as for bread (in general)" as "as for the bread (that a certain someone makes)."
This 熱い is usually used for things but not people. (e.g. スープが熱い、熱いコーヒー、etc).
If you hear "someone is 熱い", this usually means that;
- someone is enthusiastic or/and passionate about certain things. (e.g. さくらさんはサッカーの話になると熱くなる: Sakura san gets excited when she talks about soccer. )
- simply the person has fever. (e.g. さくらさんはねつがあって、(体が)熱い。: Since Sakura san has a fever, her body is hot.)
If you want to use "hot" like "she is hot.", you might want to say, "さくらさんはみりょくてきです。”, "さくらさんはセクシーです。" Sometimes you might hear ”いい女です” but this can be rude to the person so, you don't want to use it.
This type of "hot" is a slang/ a newer definition, there is no direct translation.
They are different sentence structures in both languages,
熱いバンです says "It is hot bread" where "hot" is directly modifying "bread" into a single noun phrase. It answers the question "What is that?" - "It is hot bread"
パンが熱いです says "The bread is hot" where "bread" is being equated with "is hot". It answers the question "What is hot?" - "The bread is (hot)"
The tea sentences are the same. "Hot tea" is a noun phrase in "it is hot tea", the other tea sentence being "The tea is cold" which is structured the same as this question.
熱いお茶です - It is hot tea - https://forum.duolingo.com/comment/24741912/It-is-hot-tea
お茶が冷たいです - The tea is cold - https://forum.duolingo.com/comment/23312386/The-tea-is-cold
Adjectives go before the noun they modify to create a single noun phrase just like in English
熱いパン - hot bread
冷たいお茶 - cold tea
おいしいラーメン - tasty ramen
かわいい猫 - cute cat
When we want to say that something is something else, describing a noun with another noun or adjective, the structure changes in both languages
パンが熱い - The bread is hot - [Bread = Hot]
お茶が冷たい - The tea is cold - [Tea = Cold]
ラーメンがおいしい - The ramen is tasty - [Ramen = Tasty]
猫がかわいい - The cat is cute - [Cat = Cute]
In "The bread is hot" you are equating "Bread" with the description "Is hot"
When you say "There is cold water" you are saying the noun phrase "cold water" exists