BSLegacyLauncher VS LegacyInstaller

You mean like with Legacy Launcher? https://github.com/RiskiVR/BSLegacyLauncher

Mods aren’t out for the current version yet so you’ll have to use bslegacy which you can download here https://bslegacy.com/ then once you install mod assistant just use the file course for the install (ex: 1.29.0) which can be found in the “installed versions” folder in the same main folder as the bslegacy launcher itself

there is also a client that makes a new instance of beat saber and is a little easier to use, but it wont track your hours https://bslegacy.com/

You can use BSlegacy launcher to have access to older versions without changing your original steam version. I have used 1.27, 1.28 and 1.29 on BSlegacy launcher https://bslegacy.com/

You can use BSlegacy to downgrade your beat saber version to whatever you'd like.

Use update skipper and stay on older versions. If you already updated you can use legacy launcher to install older versions. You can also manually install old mods into your mod folder, but this wont always work.

download the oculus store downgrader from this site https://bslegacy.com/

One is through legacy installer, another program that installs old versions https://github.com/Goobwabber/LegacyInstaller

There is no ETA, usually it's a few days. You could rollback for now using this: https://github.com/Goobwabber/LegacyInstaller