There should be, but I have no experience of them so I let others answer that.
Subscription services like SLR (and others) allow you to stream both video and script.
Edit: I forgot about Faptap, which is free, that chris1337 mentioned above.
Look in the how-to section of this forum. There are both video and written guides there.
It depends on the scripter and how paid scripts are made. Hand made paid scripts are mostly made by more experienced scripters, which usually means quality, and some sites have quality control on the scripts prior to release. Other sites use AI for scripting and those are not always good and almost never as good as hand made scripts. Some scripters releasing free scripts here used to do paid scripts before. So you need to try free scripts and learn who does quality work.
See 3 (the guides also contains tips). There are also other threads here with tips if you look for them.
Yes there are quite a few, but most of it is done via modding existing games rather than games having support built-in by the developers themselves. Check out this topic for a good place to get started
As chris said, faptap is a good place to go for this that’s free. I know on the Handy website there are some links to official paid partner sites that support the Handy
Most people use OpenFunScripter - it’s quite easy to get started and is quite fun, I strongly recommend trying to make some!
Generally yes, scripting is a pretty legit artform that requires skill. As you use more scripts, you’ll start to notice that the personal taste and subjective decisions different scripters make can end up having a pretty big effect on your enjoyment of a script
Depends on what kinds of tips you want! My biased advice is to check out beta.funscript.io for a few extra apps that don’t involve synchronizing your handy to videos, and for some utilities to modify scripts to your liking