Sometimes the best way to do it is to give others the opportunity to show themselves to you. In 2024, I was in a similar position as you and I decided to start a meetup group in my own city that caters to occult and spirituality. Of course, I got a lot of new age folks because I added the word "spirituality" to the title, but this also helps increase the drag net a bit more since there is always a lot of overlap in these areas.
In the process, I was radically honest about what I was offering from the occult side, which is something that might be at odds with what a few others have said. Unless you live in a place where identifying yourself as an occultist could be dangerous for yourself, then the only real risk you run is people judging you as a "freak" or something similar. If you are okay with that, then you can do this.
Just know that if you do this approach, you will probably want to be more open to all types of people who join. I understand you want to exclude certain groups of people, and that is your prerogative, but it helps to foster an open ended community that feels safe to come to your group. Invariably, the "real occultists" will come and you can then make friends 1-1 with such people. The important part is to be radically honest about what you put out. If you want the occultists, then don't be afraid to jump straight into topics like grimoires, demons, and magick directly. There is no need to sugar coat what you are looking for and this will be the quickest way to attract the correct people to yourself.
One final caveat is that you will want to be open minded to anyone who joins. Even if you are searching for LHP people specifically, then you should be open to people other walks of the occult life. Having a reputation for being a safe haven for all occultists will help the right types of folks to come and join you.