Yes it makes you vulnerable to IP theft, and it does happen. But if you look for startup founding advice, people will tell you that it's a mistake to try and protect your idea. The main arguments are:

1. Execution matters more than the idea.

2. It's always better to get feedback / test the market earlier rather than later.

3. Your IP may be protected in theory, but in practice, companies infringe on patents all the time.

See for instance here:

https://daniellenewnham.medium.com/no-one-is-going-to-steal-...

or here:

https://www.talkingquickly.co.uk/2015/04/what-id-tell-myself...