The difference in Cantonese usage couldn’t be more stark. I’m currently in Hong Kong. Everyone speaks Cantonese, and if you speak Mandarin, that says to people “This person is a Mainland tourist, let’s overcharge them.”, and if you speak English, that says “This person is a rich foreigner/white person, let’s overcharge them.”. This is despite English and “Chinese” (both variants) being official language in Hong Kong. All Government services are provided in all three languages but if you use anything but Cantonese, you’re going to see significantly more friction and encounter many more difficulties that Cantonese speakers don’t.

to be fair it's like this in almost all regions where the locals speak a minority language and they try to preserve it. In Canada they have english and french as an official language but if you try to speak english in quebec they will not be happy because of their history with the language/anglophones. you are seen as a form of colonizer if you speak a non-native language (both in quebec and in hk)

When I was there last before the pandemic I had no problems. If it's any consolation what I've noticed is that in the mainland radio I've heard them use words like

Argue (idk the word for it Cantonese because it is an English loanword that originated in HK)

Cut 線 for hang up which is another english loanword

Keep住 for continue etc.

This was unheard of even ten years ago and the younger generation when I was there have softer accents (merging slowly to HK accent). What's more profound is that they use it in broadcasts, which means more people will use these terms.

I'm happy that the vocabulary has changed on the mainland somewhat, these terms are popular in HK. Having English loanwords is good because it makes it vastly different to Mandarin so that people don't get confused between the words.

Mixing in a bit of English sounds normal in Cantonese even on the mainland is becoming more and more normal (people won't bat an eye) whereas if you do it in Mandarin people go wtf.

Having said that the accent vocab change on the mainland only affects the younger generation, the older ones use the traditional or even Mandarin terms as some of them get confused between the two. I have yet to hear anyone on the mainland older than 30 use the English loanwords.

I'm from the mainland originally but I've been overseas for a long time so my English is better than my canto. When I'm in the mainland Cantonese is easier because if I don't know a term I just put the English word in it's place, noone cares but always feel nervous in Mandarin because it's not normal to code switch.