Compared to login, MITM on registration means the culprit knows the IP address and the time of the registration, which is usually significant on claiming the account back.

I don't have a spare number to test, but I'm pretty sure entering a phone number in the web sends a SMS code. Do you have concrete evidence that it really doesn't work?

This actually is not a bad thing. If an unofficial client MITM the whole registration process, it's much harder for the true account owner to prove that he/she is the legit one.

Also, it doesn't really require a client to register; Telegram can be accessed from a browser.

Not sure about Apple devices, but for Android there's FRP (factory reset protection). Basically, if an Android phone which has FRP enabled has at least one Google account signed in, after factory reset, the phone is locked unless it signs into one of the Google accounts previously in use.

I cannot find documents about FRP from Google, but here's one from Samsung, and I'm pretty sure it's not limited to Samsung.

https://www.samsung.com/ph/support/mobile-devices/what-is-device-protection-or-factory-reset-protection-frp/

At the time I learnt English, someone told me that if you're communicating with a native speaker, the receiver is probably competent to understand what you want to express.

You should not worry too much about writing. If not sure, just use words with the same pronunciation, or even words from other languages, like "d/啲".

• Cantonese writings are not used in formal documents. In other words, we may say that all the Cantonese writings are colloquial, thus the mix use of those 3. One typical example is the subtitles in television. They're mostly formal Chinese; it's near impossible to find those 3 words there.
• Not being rude to the native speaker you mentioned, but there's a significant amount of native speakers that can only listen/speak Cantonese. This is especially true in the mainland (Canton province). I'm also a native speaker and have been using Cantonese writing for more than 10 years, with handwrite IME in my phone. I think I could be decent on answering questions about writing.
• Here's some links from a quick Google on the 3 words.

https://cantonesemuseum.blogspot.com/2018/02/blog-post_13.html?m=1

https://articles.omghomework.com/畀俾比/

Here's a more advanced but subjective one.

https://notesbooks.wordpress.com/2016/11/13/畀俾比．使駛洗/

You can see that they all mention the mix of "畀/俾" but not "比".

• Feel free to ask more questions, I'm happy to answer

Thanks for your info, but given this is near the end of the explanation of "比", this is probably rarely used. In fact, this usage gives me a feeling of being overly lazy or illiterate. My recommendation is to forget about this and use the other two when they're more appropriate.

Colloquial Cantonese writing tends to keep the pronunciation correct while the characters used vary. From your link about "畀" I can't find any references to "比".

I'm pretty sure I can figure out what the writer wants to express no matter which one is used, but it's hardly correct if "比" is used in my personal opinion.

Another thing to be aware of, it's rare (if not never) to replace "比" by "畀/俾".

• I don't think it's in passive voice.
• The "bei" relevant to your original question should actually be "畀", which means "give".
• To express the meaning of "comparison", the "bei" should be "比". For example, "我比你高" means "I'm taller than you". This is where your confusion comes from; the original sentence in your question does not really use the right word.
• Some people tend to mix the usage of 畀/俾/比, IMO the first two can somewhat be exchangeable, while the last one can't. "俾" has a meaning of being passive, "我俾人打" means "I was assaulted by someone".

I'm not a linguist so I can't really answer your question, but IMO the "的" should be "啲", which means "some". A direct translation could be "He asks me (to) send some drawings/paintings to you. "