Only seeing Omega update need to potentially get the Alpha or Delta.

If you're an Xbox Insider then you will get more updates as compared to others. Even as an insider there are 4 different rings - alpha, beta, delta and omega. Being in alpha ring will result in a lot of updates, and number of updates goes down as you reduce
your level.

If you do not want frequent updates you can unenroll from the program.

The Chromium browser was previously only available for members in the Alpha Skip-Ahead ring, but as of the last couple of days, it's not only been rolled out to Alpha members, but also Beta and Delta members. Only the Omega rings have yet to receive it.

Status July 2021

Hi Luna!

I've definitely had a similar situation before come up, usually around 3am pacific time they will roll out Insiders Updates. One of the nice things about being an Insider is getting access to frequent updates and new features, but it can get annoying if
you're receiving too many updates right when you need to be online. What I would suggest if perhaps lowering your Preview Ring tier. The tiers are as follows :

• Alpha – Open on an “invite only” basis and receives updates at the earliest point in the preview window.
• Beta – Open to Xbox Insiders with a Program tenure of 3 or more months and an Xbox Insider XP Level of 5 or higher. This ring receives updates shortly after Alpha.
• Delta – Open to any Xbox Insider with a tenure of 1 or more months that has reached Xbox Insider Level 2 or higher. Depending on certain edge cases where further attention is required from Alpha or Beta rings, Delta Insiders may receive
  system updates before Beta, though this is not a common scenario. Additionally, while early system updates are not guaranteed across the Delta ring, all Delta Insiders will receive the update prior to GA.
• Omega – Open to anyone and receives system updates shortly before the GA (General Availability) release.

If you are currently on Alpha or Beta, maybe lower yourself down to Delta or Omega? Those rings receive far less frequent updates, but still get some nice goodies ahead of everyone else. On Alpha I receive updates sometimes daily, but Delta and Omega receive
them more like weekly or monthly.

You can make this change within the Xbox Insiders App on your Xbox, going to "Insider Content" then head to "Xbox One Update Preview" under "System" and select "Manage. If you'd like more information on this, check the link below. Cheers!

https://support.xbox.com/en-US/xbox-one/console/xbox-insider-program

Depends in which insider group you are. Alpha skip ahead first, then, alfa, then delta and omega. For regular users in the same time.

They rolled out to the Xbox Insiders Alpha users, as for the rest of us that are Beta, Delta, Omega, or General Public, they have not been released yet.