I think this last point is super important! Focus on making the experience of your app crashing as not miserable as possible. Try to eliminate as much as possi

I think this last point is super important! Focus on making the experience of your app crashing as not miserable as possible. Try to eliminate as much as possible user loss of effort if your server crashes (if you have a long form a user needs to fill out, consider persisting the data and restoring it from local storage, so if the server is down and the user has to come back later to submit their data isn't lost). If you can have a not awful experience when your small SaaS crashes, then it's probably okay to aim for 2-nines* of reliability instead of 5-nines. You're not Amazon as a small SaaS, it's okay to have a little bit of downtime now and again. Your product is important, but it's also important to keep in mind your quality of life. Spending the time to polish the failure scenario, means you can be a little more tolerant of failure scenarios. * maybe slightly more than 2-nines, but that's the general idea.