Linkedin is a very handy tool to have - even if you’re not looking for a new job - it’s good to connect with people in your industry or company etc.
You can gain a lot of useful information from it and the more active you are on it, then there is more chance of you being noticed by a headhunter.
Downsides is that, as you say, profile is public and anyone (including those not on linkedin will be able to see your work history etc) - You can change the settings though so that only your first name and the first letter of your surname is on your account until you accept a connection request. The only other downside to it is that you often get sent spam or messages that have no relevance to you. I have known some guys to use it as an extension to Tinder……
LI is what you make it really. It’s a good tool to have.

I like it as you can post / read / interact with work related chat whilst keeping it totally separate from any social media.

The job search / alert function is excellent

I regularly receive messages from head hunters. Not had the perfect thing come up though so I always reply politely and thank them for being in touch, then refer them to other people who come to mind

Tools and tutorials on improving your CV, interview techniques, profile etc are excellent

I like being nosy and seeing what former colleagues are doing, many of whom I’d otherwise have lost touch with

You can block the ex. I use LinkedIn a lot. I'm contacted for jobs fairly regularly. It's a networking site. So network properly on it. If you're passive it's a bit pointless.

I also regularly apply for jobs that interest me. At a minimum good interview practice. Also did a lot of LinkedIn learning that started my retraining and new career.

You can block people on LinkedIn.

You don't need to provide full employment history either. It's not your CV - more of an introduction to you.

LI is a useful tool but not the only one in town so you will still need to keep scouring other websites and checking recruiters out, especially if you are fairly niche.

I too, am fairly niche, and haven't always got the whole algorithm thing sussed. Like today they claimed I was a perfect match for jobs in transport, finance, engineering and sports. None of which I am remotely experienced for.

You can set your privacy levels to be only visible to recruiters or connections. And my advice would be to do that. There are a lot of oddballs on there and one colleague had her CV lifted and used fraudulently to apply for the job she was vacating. Luckily HR clocked it and asked her about it, but like all things online personal safety is paramount.

Probably shooting myself in the foot, but I refuse to use LinkedIn because they are such terrible spammers. I get, or used to get, endless unsolicited emails from random people who wanted to "add me to their network". I'm sure they were actually generated automatically.