Why choose an older DSLR for cheap used lenses over mirrorless for beginners?

[Stephen61]

I'm finally ready to upgrade from my phone to a real camera, and I'm stuck on the classic dslr vs mirrorless for beginners debate. The tech specs are overwhelming, but my main concern is actually about the used market—it seems like there are way more affordable DSLR lenses out there. Is that a good enough reason to start with an older system?