Beeper is just matrix with a bunch of preconfigured bridges for you. I've deployed a few of their bridges (as they're open source) for my own matrix server and can confirm they work perfectly.

Haven't had whatsapp installed on my phone for over 2 years. I even support the devs via github sponsors, I'm that happy with their bridges.

If you're not technical but want the benefits of bridging other networks into Matrix, Beeper is a great choice.