There's a bit of secret sauce here that I tend to rely on to prevent myself from being considered "that guy".

First and foremost, I do this as much as possible via e-mail. Phone or WhatsApp is indeed too "personal" for these type of things (save for one person, an old boss of mine, who I have a scheduled zoom call with once a month. But that's just because he and I just like the chit-chat, it appears).

I write up a long-form message, something like 5-8 paragraphs with real news about myself and the things I've been up to, and ship that alongside the usual casual chit-chat.

It's surprisingly useful - I think this is the only context in which long-form e-mail is a good thing.

But then again, I grew up in an era where e-mail is the devil, and this was not always the case (or so they tell me).