With the recent issues with Slack and GitHub, it seems required to say this. If you are using a SaaS product there is written communication (SLAs) stating what you as a consumer are willing to accept from the provider and that you (implication) as the consumer have performed the risk-benefit analysis to determine if that SLA is appropriate for you. If Slack or GitHub goes down, it is an inconvenience for that time period but one you have accepted because for your company it outweighs the inconvenience of:

Hiring people
Having those people deploy alternatives to Slack and GitHub in a private cloud for you
Having those people operating and maintain the alternatives

If we look at this list (and assume we deploy into a cloud provider) you need to pay salaries, possibly licensing for the software you want to use, and the usage cost in the cloud provider (paying the license fee and the usage cost, I will take a shot in the dark and say is already being calculated in the cost of your SaaS provider, you don't get anything for free

People don't buy phone apps, they pay for services. Meaning that if you make an app, you won't make money for that app unless it is service based. There are a few outliers to this.

Games are different than this as people will pay a set amount of money for a game to own, but they will also continue spending money on the game via microtransactions or 'packs'.

Most people don't care about their security or privacy - but that's all the more reason to make it clear that you respect their security and privacy.

Everything should be opt-in, not opt-out in terms of data collection, marketing, and advertisement.

It should be very clear that if someone is not paying for a service or tool, that the ads are what provides the revenue.

Enterprise software is weird as there are many regulations associated with it and the company has every choice to go with an open source alternative, of which one most likely exists. In other words - don't aim for enterprise use at first. Make something that fixes or solves the problem that you have first.

I have changed my mind here on the following:

The majority of people use their mobile device (Phone) as their gadget, they aren't using a desktop or a laptop if they even have one. If you want to attract the attention and get users, you need to meet them where they are.

This doesn't mean make a Phone app that is just a front-end that goes to a responsive web app. This means, make a full-featured phone app. They have more power than early 90s and Y2K computers, take advantage of it. What we have seen from ChatGPT is that if people want to use the service enough, they WILL use a website even today. An app is not required.

I have changed my mind here. If you limit yourself in an area of marketing or user-space, create an ecosystem where multiple platforms and apps can coexist and depend on the progress of another.