Just about anything is technically doable, however turning 50k into 3k/mo in only 5 years is probably not realistic. It would take roughly 1.2m in 3% dividend paying stocks to earn that much. So while 50k is probably enough to get you started in real estate, it is nowhere close to being capable of generating that kind of reliable income without serious growth. In the long term real estate will make you wealthy, but it won't do it quickly, and the cashflow won't be nice and uniform where you can quickly start living off of it in the first few years to upgrade your lifestyle.
Cash flow can be tricky until you scale to a large enough portfolio where your expenses tend to balance themselves out each month. Lets assume that you run your numbers, and after accounting for projected expenses like vacancy, repairs, capex, management etc, you think the deal will bring you an average of $300/mo. However, there is never a month where you will actually get 300. Instead your bank account will likely increase by 800 most months because you didn't have any expenses for that month, and then you get hit with a major expense like a new HVAC unit and have to pay $7,000, thus wiping out 2+ years worth of "cashflow". And then the tenant moves out and it takes you 30 days to find a replacement tenant so you have no income for the month, and you need to repaint the interior costing another 2k. For this reason, it can often be tricky to try to retire, or otherwise count on your cashflow to live off of during the first few years of ownership. You can't reliably spend your 'cashflow' on living expenses, because you don't know when that next big expense is coming and therefore you need to keep that cash on hand instead of spending it.
Historically real estate has tended to go up in value by roughly 4% yearly on a nationwide level. This doesn't sound so great when you consider the stock market averages closer to 10% yearly. However the key difference is leverage, so if you buy 50k worth of stocks, and it goes up by 10%, you have made a 10% profit, or 5k.
However, if you had taken that 50k and used it to put a 5% down payment on a 1m duplex, or quad where you plan on living in one of the units, and that 1m property goes up in value by 4%, then you have made 40k in equity, which is an 80% returns on your initial 50k investment. Now add in a little bit of equity paydown as you are slowly repaying the mortgage balance, and add a little bit for some theoretical cashflow, and add a little bit due to all of the random tax incentives landlords and small business owners get. Once you start adding up all these little bits, its starts adding up to a lot, and when you start compounding that over a handful of years, and using the proceeds to purchase additional properties, it can quickly snowball into generational wealth.
Appreciation and equity paydown are by far and away how the majority of people get wealthy in real estate, the cashflow is a byproduct that tends to come later once you have had several years worth of rent increases. Lets say you hypothetically initially rent a house for 2k/mo and are essentially breaking even and not making any cashflow. If home inflation rates are roughly 4% per year, then it stands to reason that in general you can probably get in the neighborhood of 4% rent increases per year. So while you start renting it for 2000/mo, next year it will likely be closer to 2080 etc. After 6 years you are now making $500/mo in cashflow, since for the most part your big expenses (mortgage) have stayed constant, but you are earning more money from rental income. After 10 years the house will cashflow roughly 1k/mo.
These numbers are of course generalizations. Some years real estate goes up in value a little bit, some years it goes up a lot, some years it goes down. But over a long enough investing period the numbers should more or less balance themselves out and become fairly reliable.
As Bruce pointed out, the alternative is to buy and remodel a piece of crap house. These have the potential to earn a lot of money very quickly. With the obvious downside that it is a more risky approach, especially if you are not familiar with remodeling, design, appraisals, remodel costs, holding costs etc. It simply takes more knowledge to be able to consistently have positive outcomes flipping homes, and buying a property that has unexpected expenses can quickly tank a project. There is also additional risk when first starting because you will need to pay the mortgage for several months while having no rental income to offset the mortgage, as it will take you several months to remodel the property and be able to either sell it for a profit, or get it ready for a renter. So your carrying costs can be quite large. Not to mention that this is typically more time intensive and is more closely related to having a second job, than it is to investing.