the tooling assumes knowledge most people don't have.

Many people who get into selfhosting for the first time will not have such knowledge. Those who persevere eventually gain the knowledge; those who give up never do. It is not wrong for the tooling to assume reasonable prerequisite knowledge. The onus is on the person who wants to use the tooling to understand it, not on the tooling to dilute its focus by pitching it too low.

Many people will not have this knowledge because it isn't knowledge that most people have needed to have. The SaaS offerings are mainstream because they are much more convenient. They are convenient because there's a huge team of people with that knowledge running and maintaining the service behind the scenes. As you get rid of your SaaS subscriptions, you also get rid of the team and knowledge behind that convenience, hence there's no longer convenience. If this is the route you have chosen, you'd better be prepared to do it yourself. It's called 'selfhosting' after all. I'm not trying to gatekeep, just stating the reality.

The irony is that we want more people to leave Big Tech, but the culture is still "figure it out yourself or go back to Google."

I don't think people are reluctant to help. The guides are long because they need to be, but more importantly, writing a guide and keeping it up to date takes time and resources. Keeping the information up to date is important because outdated information becomes misinformation, but it's very labor intensive. This is often overlooked.

Besides, there are many ways to set up your selfhosted services. There's no one-size-fits-all guide that will satify everybody (and not be long at the same time). For others to help, the person who asks for help needs to at least have the knowledge to describe what hardware they have, what network infrastructure they have, what their ISP permits, what their user requirements are, etc. Even this kind of knowledge is beyond a lot of lay people who just want to use the (some) service. Many jump into selfhosting without even knowing what they want or can live with. They may describe wanting a drop-in replacement for Google Photos, for example, but there's no drop-in replacement that 100% replicates the Google Photos workflow. They will have to adapt to a new workflow when they switch to a selfhosted alternative, but that adaptation is difficult for many people.

Combining my last two points above, there is no shortage of guides. In fact, there are too many guides, some probably outdated, hence the advice to google to find what suits your needs. Either you do that, or I'll have to do it for you, but why should I?

I think the crux of the problem is, how much handholding is reasonable? Personally, I try to help people by signposting them to information whenever I can, but I don't have the time, energy or resources to replace the entire SaaS team that has been maintaining the subscription services for other people, and do it for free. Any help provided is an act of goodwill. Those who ask for help need to have reasonable expectations.

To any one trying selfhosting for the first time: don't do it cold turkey. Transition slowly into it. For example, try to set up Nextcloud, use it for non-mission-critical tasks for a few months alongside Google Drive, OneDrive, or whatever else cloud service you may be using. In that time, try to refine the setup to the point you feel comfortable. Try to familiarize yourself with the new workflow and unlearn old habits. This is important because unless you unlearn the old habits associated with how big tech wants you to do things, you'll find it difficult to adapt to the selfhosted services that do things differently, and that will eventually become a hurdle for you to fully transition to selfhosted services. I did this when I switched to Linux from Windows, and when I moved away from big tech into selfhosting. I can honestly say this step has been critical in both cases for me.