

I ran the numbers and got 17 months.
Although realistically if I stopped receiving any income my monthly spend would drop - I would certainly spend less on food and luxuries, which would buy me at least an extra 2-5 months.
I know you excluded it, but again if my income stopped then at some point I would sell my house. if I used the sale money to pay off the mortgage and then start renting a flat I could go without income for about 8-10 extra years (that surprised me!).
There are a load of resources online. The UKPersonalFinance subreddit is a good place to start, and a lot of the advice is applicable outside of the UK too. If you don’t want to read or think much, then just pick a broad index fund with 0.2% or below of fees and put your savings in there.