As it turns out, none of the services I run from my living room NAS or the one that I have hosted on a dedicated machine elsewhere had an issue.

Without knowing more about your situation, the standard advice would be something like:

1. Pay off any debts, credit cards, etc that you have.
2. Top off your emergency savings. This should be somewhere between 3-6 months of expenses.
3. Put the rest if any into retirement, probably an IRA.

Two points though:

1. Take some and have fun with it, maybe $2k-4k. Get some nice clothes, laptop, take your SO to a very fancy restaurant.
2. $15k as pocket money for a 19yo?!? That’s a generous brother in law.