I've been trying to use this VSCode extension for years now. At first it had major memory leak issues (I reported these). I believe these to mostly be resolved. I then decided to give it another shot and have spent a few months using it and I must say, it's very frustrating.
It's just too slow. You can make a change and then you have to wait around 5 seconds for it to reparse all the code and update the file. It doesn't always do this. But it's quite frequent. Sometimes it never updates too. It'll report something like "Call to unknown method", when in fact it's not. The method call is perfectly fine. It's like the cache never gets updated.
I don't know what other objectives there are with this extension, or what the overall goals are for it. But to say that this is the most important issue is an understatement. This is a pre-requisite. You guys need to drop everything else you're doing and fix this. Until then, it's not usable and I'll be switching back to Intelliphense again. I don't even know if I'll give this extension another shot, to be honest.
It's running on an M1 Max, which is very fast. It's not a resources issue.