I followed this recipe on YoutubeMaangchi-Vegetarian Kimchi

It has two components that bring the bright red color. One of them is Gochujang- a fermented chilli paste which is not at all spicy but has a strong umami flavour. The second one is gochugaru- red chilli flakes which are pretty spicy. If you’re trying to make Kimchi you can totally skip it.

If you get to try Kimchi at a restaurant it’s probably not too spicy and mellow.

No it’s mostly uses a base that has either fish sauce/oyster sauce/shrimp paste/anchovies etc. I’m not Korean but I have made Kimchi a lot of times and I’ve noticed that every family/bloggers have a different version of Kimchi. So it’s a very versatile dish and takes a couple of tries to get it right based on your preferences.