Hi, I’m a casual linguistics nerd (no degrees), speaking Philippine English with heavy American influence.
My accent of English has pre-nasal /æ/ raising and I’ve caught myself raising it in other places like before /g/.
When I look at English language learning videos (out of curiosity) I have not found anyone mention /æ/ raising in them.
Why is this case?
It’s certainly true that many British English dictionaries are quite out of date with their pronunciations, with many still using the RP accent which you almost never hear in Britain nowadays.
There are some who are updating things, like Geoff Lindsey and his SSB CUBE (CUrrent British English) dictionary (although they haven’t updated to have https, for some reason).