Don't feel like a fool: we've all been there. It's a learning curve. You'll teach yourself brilliantly.
Watch that creepy neighbour though. Your alarms bells are ringing for a reason. 60 isn't that old -- he could still try to press himself onto you. Better to blank that arsehole before he's sleazed his way into your front room and he has you pinned up against the wall. Don't give him an inch. Or anyone else, for that matter. You don't have to smile, or be polite, or give anyone the time of day. You owe these fuckers nothing. Nada. Zilch. 'Staying empathetic' sounds like a shit strategy to me. There's a word in there... begins with a 'p'... Don't be that. Blank him. Don't even look at him. Let him get his wife or daughter or carer to fix his problems. He'll get the message. And if he doesn't, he's stupid.
The rest of them? Fetish guy? As soon as he started behaving in a way you're not into: you dump. No need to explain, to soothe his manly feelings. Block. Ditch. He'll try it on with somebody else. You know he's probably messaging another fifteen girls. Let one of them listen to his nonsense.
NPD guy. You met him IRL once, and 'decided' to trust him? Nah. It takes years to really get to know somebody. You know that. Don't be so... nice. Doormats get walked on. Don't be a doormat.
Anyone who tells you they're lonely. Nah. Normal people have friends, family, careers, hobbies. If they don't, there's a reason. Anyone who has 'problems' they're sharing with you within a date or two? Nah. You want light, fun, easy. As soon as it isn't... bye.
I think you're making a good decision when you decide not to chat to random online. I know that's how dating allegedly is, these days, but if it leaves you wide open for these oddments to prey on you, I wouldn't bother. It's not just you, you're not some unusual case or some idiot that needs to fix yourself: this seems to be how it is for everyone. OLD is a con, imho. There's all these lovely men available? Nah. Most of them are... ugly, married, weird, desperate, dangerous or dumb. Fishing for random dudes online is like... using a deep-sea dragnet. It stirs up all these bottom feeders...
Fish in the cleaner waters would be my advice. Date the old-fashioned way. Pretend it's still 1950. Ask around in your circle, who's got a single friend, a cousin, a brother. Let your best friends sister set you up. Or Jean from human resources. You're not looking for marriage, and babies, yet, probably, but you're looking for something special. Not just any old thing. You're choosy. You want the best. Where do you work? Do you have any hobbies? Look out for the eligible bachelors. Get the gen on them, find out why they're single, try to chat to their ex-girlfriends, meet their friends, their parents, their colleagues, before you do anything you might one day be ashamed of (grin). Sure, it's not 100% fool-proof, some slime-ball might still slip through the net, but at least this way you get a better chance to weed out the cock-lodgers, sleazebags and no-hopers before you let them into your heart (or your pants).