I would not expect to replace your W2 income in the first year and would project it to take 2-5 years before you were able to replace it, unless you are sitting on around 3-5M right now.

Examples include replacing a deck or renovating a kitchen.

If you're insuring a home to replacement cost, insurance companies don't care about appraisals or what the home is worth.  

I'm interested in learning about rental property investment, looking to build a rental portfolio, exploring real estate investing to replace my income.

Maybe not meant to sound that way but it comes off like that to me.

Even in a lower priced investment property, like a small SFR, what does the investor without a contingency fund do when say the ac or a furnace need replacement?  

It sounds like they have been paying, maybe talking to them about your concerns can help them better meet your expectations.

I need to redo the roof of the house lift up the second floor, the entire front deck of the house, demolish the old stucco, And replaced a lot of rotten wood and messed up beams.does anyone have any recommendations? 

Central A/C is damaged beyond repair and needed to be replaced, which can't be done economically or with coopperation of the HOA and other neiighboring owners.

Here are some of its vitals:- Zestimate: $345K (I know this is typically 10% or so high)- Last Sold: 8/2021 for $281K- Roughly 1400 sqft- Some cosmetic work needed- $25K left on solar loan- The home was build in 2004 and it looks like it has the original AC unit, so I am assuming that needs to be replaced too. - 2 story house with very small rooms and and 2 steps down, imminently as you enter the front door.- Gated community and in a reasonable HOA. - The home is 2 payments behind and already got a letter from the lender about future foreclose.