It’s all ground karate/struggle snuggles with different rules.
Honestly Khabib does a lot of stuff that’s a little bit atypical from both bjj as well as sambo. At this point he’s basically a hybrid grappler and honestly the way he controls on the ground is way more like folkstyle wrestling blended with bjj than it is sambo.
I love sambo. I’ve done sambo, judo, and bjj. Bjj became my biggest love bit it was my last love. I enjoyed sambo way more earlier on. But in mixed grappling arts rule sets like the biannual ADCC (which happens later this month actually) bjj athletes tend to do the best.
For example sambo used to be known for meg locks but the bjj nerds took over a few years ago and took leg locks to a higher level than ever seen.
All grappling is dope as hell though. I still love sambo.