Yes, SBRS and SDR are different, and you want both.
SBRS is based on IP reputation, and before the rise of cloud email at large scale, it was fine.
But with more and more people on cloud platforms, you can't tell if that email coming in from a random Microsoft IP is good or bad based purely on the IP its coming from.
Sender Domain reputation is based on the domain name the email is coming from. And it can check things like age of the domain, as well as reputation.
So you do want an SDR content filter to catch things with "awful" reputation at the very least... and domains younger than 40 days or so...
Ken