Welcome to the forum!
Your question is based upon the wrong premise. Manjaro does not get updated once a week, nor is there any other set periodicity to the update process.
Manjaro is a curated rolling release, which means that unless it concerns a high-priority update ─ e.g. an urgent security fix ─ updates are bundled together. This way, you don’t get updates every day or every couple of days as with many other rolling-release distributions, and the update process is actually more of an upgrade.
For the Stable branch, the updates are usually issued once or twice a month ─ sometimes three times, but that is rare ─ and even though it is often possible to skip an update, it is not recommended that you do so.
If for whatever reason you don’t want to update Manjaro more than once a month, then perhaps a rolling-release distribution is not for you, and then you might be better off with a fixed-point-release distribution.