particles - Use of が with certain adjectives

Recently, the が particle has been a little iffy for me especially with adjectives.

Some nouns when modified by an adjective can seemingly use が　and は interchangeably while others cannot, is this correct? Can you guys confirm my understanding here and elaborate/explain some of the nuances I may be misunderstanding.

So, from my understanding the following 3 examples are grammatically correct and translate as follows. However, is there any fundamental difference between example 1 and 3 where one sentence uses は while the other uses が ? What kind of situations would one use が as opposed to は in these types of sentences?

1.) アイスクリームが美味しいです　-> Ice cream is delicious

2.) アイスクリームのほうが美味しいです -> Ice cream is more delicious

3.) アイスクリームは美味しいです -> Ice cream is delicious

However, there seems to be a subset of adjectives like 好き, 嫌い, 上手, 下手 and so forth in which は would be inappropriate and not make sense. Is this correct?

4.) アイスクリームが好きです -> I like Ice cream (appropriate usage of particle, が）

5.) アイスクリームは好きです　-> I like Ice cream (doesn't make sense needs が）

Thanks!

Answer

が sounds like you have a topic already, for example you're talking about desserts at a particular restaurant:

アイスクリームが美味しいです。
Out of the desserts at this restaurant, the ice cream is delicious.

This is just how you express the comparative in Japanese:

アイスクリームのほうが美味しいです。
Ice cream is more delicious.

は sounds like you want to talk about ice cream "out of the blue":

アイスクリームは美味しいです。
Let's talk about ice cream. Ice cream is delicious.

These "adjectives" are adjectives English, but in Japanese need a "topic" (marked by は) and a "subject" (marked by が), where the topic is usually someone (X). If X is not given, it is assumed to be you (私).

[Xは] アイスクリームが好きです。
X likes ice cream.

アイスクリームは [Xが] 好きです。
Ice cream likes X.

There is a different は, used to mark contrast:

[Xは] アイスクリームは好きです。
X likes ice cream. But doesn't eat anything else.