For it to eat the entire sun, you are correct. But for it to destabilize the orbit of planets through the orbit of a binary system, it is quite plausible once

For it to eat the entire sun, you are correct. But for it to destabilize the orbit of planets through the orbit of a binary system, it is quite plausible once the blac hole has gained sufficient mass for it to count as a binary system and not simply a planetary mass black hole orbiting a stellar mass sun[1]. [1] https://arstechnica.com/science/2013/01/binary-star-systems-make-for-unstable-planets/ https://arstechnica.com/science/2013/01/binary-star-systems-...