I am looking for several things:Some advice or brain storming on what the best structure is for my businesses whether it be Umbrella, DBA, individual llc, or other? 

Talk to an attorney but if you own the properties yourself a umbrella policy might be good enough.

How you setup your business structure and perhaps tier/layer your LLC (or any other business entities) is up to you.With 4 (assumably residential rentals), you'll see many on BP just use insurance with an Umbrella liability coverage and keep their properties in good repair.Of course, consult with a qualified professional or two...Good luck.

Plus, you can have just one umbrella policy for the LLC to cover multiple properties which is much more efficient.Yes, if you are highly concerned about a lawsuit, then you need to establish LLC(s), refinance/finance with commercial loans (whose rates and terms are less favorable than conforming residential loans) so the mortgage is given by the LLC (and not you), and operate the LLC correctly to protect/maintain its corporate veil.So, sounds like you want to slowly change your existing LLC to a holding-type LLC? 

I'm having trouble finding information regarding potential E&O.My current agent (State Farm) says that the General Liability attached the the property in addition to an umbrella is sufficient.

Since I spent about 500 to open the LLC , at this point should I just keep it and take out a umbrella insurance for all 6 properties?

I have top shelf time tested PMs, and quality liability insurance fine tuned with umbrella insurance.So I achieve asset protection the old fashion way, I earn it.

I didn't use this before and don't know whether buying umbrella could be better than forming a LLC. 

Until that time I got an Umbrella policy on all my properties for extra liability protection. 

Both my properties are registered on my personal name and I have an umbrella insurance.Since I'm planning to expand my portfolio, I'm looking for some tax and legal advise (for my 2021 taxes and to evaluate if I should move my properties into LLCs).