Correct me if I'm wrong, but a good way to sniff out LVM early on is to pay attention to whether or not they uplift you.

If you're talking about accomplishments, he won't sound genuinely happy for you and might change the subject a little abruptly. If you're talking about failures or hardships, he won't comfort you in any way. He will just look at you and maybe give you some false platitudes.

When talking about your future goals, he will introduce doubt or condescension.

The one exception to this rule is charming men, who are experts at coming off genuine and are socially savvy enough to say exactly the right things. Different rules apply to them.