You could spend some time doing market research and eventually find a niche, an underserved market that was still pretty good with stable/reliable sales, solid comps and investor interest.

Are they ususally reliable?

Security:Weigh Costs and Benefits: While maintaining an LLC and having comprehensive insurance can add costs, they provide significant protection against risks.Professional Advice: Consider consulting with a real estate attorney and a tax advisor to tailor your setup to your specific situation and goals.By structuring your rental property thoughtfully and taking these precautions, you can better protect yourself and manage your investment effectively.

Here are some options and considerations:Loan Against Equity/ETFs:Margin Loans:Description: Margin loans allow you to borrow money using your investments (such as stocks or ETFs) as collateral.Pros:You retain ownership of your investments.Generally quick access to funds.Interest rates can be relatively low compared to other types of loans.Cons:Your investments are used as collateral, so if their value declines significantly, you may face a margin call (requiring additional funds or securities).Interest rates can vary and may be higher than traditional loans depending on the lender and your creditworthiness.Securities-Based Line of Credit (SBLOC):Description: Similar to margin loans, SBLOCs use your securities (stocks, ETFs) as collateral, but they typically provide more flexibility and may not trigger margin calls as easily.Pros:Allows for ongoing access to funds as long as your collateral remains sufficient.Interest rates may be competitive.Cons:Similar risks of potential margin calls if the value of your securities drops significantly.Terms and interest rates can vary widely among lenders.Comparison with 401(k) Loans:401(k) Loans:Description: Borrowing from your 401(k) allows you to access funds without selling investments, using your retirement savings as collateral.Pros:Typically low interest rates.No credit check required.Interest paid on the loan goes back into your 401(k) account.Cons:Usually capped at a percentage of your vested balance (commonly up to 50% or $50,000).If you leave your job, the loan may need to be repaid immediately or could be considered a taxable distribution.Potential opportunity cost of missing out on market gains if funds are withdrawn from investments.Other Alternatives:Home Equity Line of Credit (HELOC):Description: If you own a home with equity, a HELOC allows you to borrow against that equity at typically lower interest rates than unsecured loans.Pros:Lower interest rates compared to other types of loans.Interest may be tax-deductible if used for home improvements (consult a tax advisor).Cons:Your home serves as collateral, so failure to repay could result in foreclosure.Personal Loans:Description: Unsecured personal loans can be used for various purposes, including investing, but typically have higher interest rates than loans secured by collateral.Pros:No collateral required.Funds can be used for any purpose.Cons:Higher interest rates and stricter eligibility criteria based on creditworthiness.I am a loan officer and we do some of the loans stated above.

Act quickly to ensure the issues are addressed, and consider consulting with a lawyer if you need further legal advice.

It's important to thoroughly vet potential tenants to ensure that they are reliable and will take good care of your property. 

Is it recommended to have a LLC and who can help creating a LLC (tax consultant or lawyer)? 

If you're seeking a reliable income stream, checkout Cleveland.

Not being familiar with California laws I would advise consulting an attorney to attempt to either raise the rent if possible or to evict.

The positive is that the payment is reliable.