There's a stark difference between giving clearly unsolicited advice, and giving advice because the other person asks for advice.
Then there's the grey area where you have to rely on non-verbal and implicit communication because it's unclear whether any advice given will be perceived as presumptuous or as pure gold. This is the murky area of human interaction where intuition matters more and formal rules don't always apply.
There have been times when I resisted advice given to me. Only to understand some time later that the advice given was really helpful and true, and ending up grateful for having that person not holding back on me.
The phrasing indicates whether the sender thinks of themselves as someone who has all the answers vs someone who just found out that something works for them.
It can still be an advice, in the sense that I may be sharing some lessons learnt, but without the patronizing tone that you describe (which I also find really annoying to deal with).