This is probably not the answer you're looking for, but you might consider buying an existing business and doing that. You could check Loopnet for some ideas.
For example, in the Denver area (just to pick a random place), there's a laundromat for sale for ~260K, with gross revenue of 214K and an EBITDA of 120K, which would certainly satisfy your 3K/mo revenue requirements. Link here: https://www.loopnet.com/biz/Business-Opportunity/under-contr...
I'm not a laundromat owner, though I know a few of them, and they aren't 40 hour/week jobs. It's not totally risk free, but it's not a terrible job.
Consider opening a Crossfit Gym: https://www.loopnet.com/biz/Business-Opportunity/established...
Or a Dog Kennel/Spa: https://www.loopnet.com/biz/Business-Opportunity/successful-...
I think a lot of us think that tech is the only or best way to make a bunch of money, but Hacker News is also a place of bustling entrepreneurship and starting your own business doesn't have to mean starting a SaaS company. You could write your own pet kennel reservation software, for example, and then dogfood it (ha!) until you feel comfortable spinning it out into software that can be sold to other pet kennels around the country/world.
I have no idea if this is useful to you, but I think it's a fun idea. I'm considering doing something similar to this myself, when my current job ends.
Good luck!