Do you still have SDK2 projects that you wish were Udon? Soon you will be able to convert them to SDK3 and CyanTriggers with one button click. Here is an early look at the project. In the video, you can see my first world "Lab Escape" converted into CyanTriggers.
This project is still in early development, but the goal is to make conversion as seamless as possible. Currently most VRC_Trigger Events and Actions are converted, but I plan to look into converting UI events as well as Standard Assets. There are a lot of edge cases to getting this to work properly. I already know some things will not convert cleanly, such as buffered events used to sync.
While I have no date for a full release, I will provide early access to patreon supporters once the project is more stable.
Edit: Looks like I will aim to have an early prototype out by the end of this month with support for triggers, and not ui events or standard assets. It's somewhat usable now, so why hold it back. Just remember to back up your project before converting!