So far updated 3 computers with no problems. All 3 of them feel more responsive and overall faster.
You just have to wait:
Approach on update availability and rolloutIn this work, learn and connect from home environment where people are relying on their PCs more than ever before, we are taking a measured seeker-based rollout approach to the October 2020 Update. We are throttling availability over the coming weeks to ensure a reliable download experience, so the update may not be offered to you right away. Additionally, some devices might have a compatibility issue for which a safeguard hold is in place, so we will not offer the update until we are confident that you will have a good update experience.
However, if you want to upgrade immediately, Microsoft supports multiple ways to install a new Windows 10 using the Media Creation Tool and Update Assistant.
Found an issue
When updated through Windows Assistant there shall be two Edge versions installed on the system, v84 (came with the ISO) and newer v86 (which was already installed).
I noticed this with HiBit Uninstaller which shows that Edge weights near 1Gb now.
Do not try to uninstall Edge until Microsoft fix this as you won't be able to reinstall it unless you use force like I did.