They‘re the exact same. By the way, I’m a native English speaking and have no idea what a „gerund“ is.

Hi Anna, The difference between "I like watching TV" and "I like to watch TV" is this: "to like" is a verb that can be followed by a verb in the infinitive form and by a gerund. When it is followed by a gerund, it expresses a liking or a disliking. For example: "I like cooking" or "I like getting up early." When it is followed by a verb in the infinitive form, it expresses a habitual preference, something that we do not necessarily like or enjoy but consider as useful to do. For example: "I like to cook" or "I like to read a book before going to bed." I hope my explanation was clear and easy enough for you to understand it clearly :-) Feel free to get in touch with me if you need more help with improving your mastery of English. I would be glad to help you. See you soon, Alex

In these sentences there are no different. But, I like to dance with him(only with him!without him I hate dancing). I like dancing(I like moving). For me, as I think, better use gerund.

Both say the same you like watching TV.

In practice, none.