Does pirating movies that are only in cinemas have a different result to when they are released on disk/streaming services

The baked in garbage is a result of you using shitty sources, possibly because there are few good sources available and thus you find more of the shitty ones.

Usually while the movie is not released digitally, only low quality copies are available. Many sites/groups don't bother with those because few people want to watch that.

I'd just wait for the release. You'll instantly find stuff that's not just clean, but also in a decent quality.

It’s rare to get a high quality pirate copy until the movie is released on disc or streaming services. Once that happens, you’ll get perfect copies. Until then, it’s probably a “CAM” version which means somebody filming it in the cinema. The betting/casino ads are common with those these days.

If it doesn't get leaked or streamed, it's usually just a cam (filmed with a camera). Honestly, I've never seen a good cam video, and they all have weird ads like you say. It's better to wait IMO.

The Barbie Movie was on there quick! I'm still waiting for Oppenheimer.

Content without baked in ads are available. You just gotta look for it. I still recommend the movie web (dot) app

The releases with ads are often CAM or TS releases which are recorded at the movie theater with a camera

At least torrentgalaxy marks ad-ridden releases with a small red "ad" label which i filter out with a ublock origin filter torrentgalaxy.to##.fa-adversal:upward(3)

On other sites releases with ads might have the advertisement in the name like XBET

I'm usually not in a hurry to watch the newest movies so i wait for the webrip/dl versions of which the highest seeded versions have an extremely low probability of containing ads

Is this just a feature of piracy?

Nope! It's just that the only way to acquire a movie exclusively released at the cinemas requires people to go there and record it with their phones/cameras, and since you can get caught and fined for doing that, the only people doing it nowadays are those sponsored by those super shady betting websites... fair enough I suppose.
Once the movie makes its way to streaming services (or to Bluray/DVD) you'll be able to get a high quality copy without any crap baked in.

Now, specifically about Saw X: There are rumors it will hit Streaming sometime in October, but I haven't found a reliable source to quote about this.
If you are absolutely DYING to watch it, there's the "Will1869" release, which has all the ads removed, but unfortunately has a watermark bouncing around on the screen.
There's also the "Telesync.x264.Dual.YG" release, it comes with dual English/Spanish audio, has no watermarks and a single, audio-only ad on one of the quieter scenes, but has rather muffled audio and the post-credit scene is in awful quality, so.... unless you can live with the watermark or the muffled audio you might just have to wait until the Streaming release comes. Hope this helps!

Yeah, you have to wait for a physical/digital release if you want high-quality rips.

You downloaded fake files. Bad actors and movie studios know all too well their exclusive theater-only film is going to be a target of pirates. They flood torrent sites with fake versions of their movie to dilute the pool of cam rips with bullshit to make it harder for pirates to download their film.

Saw X is still in theaters. Therefore, the best you can hope for is a handheld camcorder version of the movie.