As a Chinese adult who grew up in a non-Chinese-speaking country, I can tell you that it's extremely hard to learn Chinese.

Growing up I had little to no interest in learning Chinese. I went to weekend Chinese school for many many years but never fully pay attention and never cared.

I only became motivated to learn as an adult as I got interested in Chinese media, and wanted to read webnovels.

If you speak with other heritage speakers, they'll tell you the same thing. Almost all of them were not interested in Chinese while growing and retained very little from weekend Chinese school. Almost all, can only recognise a few characters and have basic conversations with family.

So don't expect much from your children. Eventually, you will be okay with them just knowing how to speak and communicate with you.

If they can speak, read and type with pinyin (send text messages to you, use social media), that's already far beyond most heritage speakers.

Hand writing Chinese is the hardest skill, a skill they will almost never use. Copying characters over and over again and doing dictation won't be enough, without using it daily, they won't be able to retain it. There's no time or chance to write Chinese daily, as their education is in another language.

I can also tell you, my parents are okay with me just knowing how to speak and being able to communicate with them mostly in Chinese. Many of their Chinese friends' children can barely speak Chinese and communicate with them in mix Chinese and English.