It is difficult to communicate with elders. What topics do you think will not be embarrassing?

It depends on what your elders know or are interested in.

If I'm at home, if I'm chatting with my elders, the topic will basically revolve around my daily life. For example, how much eggs cost today, what vegetables have gone up in price, how cucumbers are raised, etc. These are all things that my elders care about, so I will talk to them about this topic.

You can also follow this principle, so that you won't be embarrassed to talk about topics that your elders are interested in.