> For people that mention software like Ledger, Excel and Google Sheets to do their accounting, what do you do to make sure you don't accidentally delete/duplicate/edit a transaction and how do you import the latest transactions in an automated way?

I make sure by reconciling my accounts weekly (verifying them against the actual bank/brokerage accounts). I don't import automatically, I found that that led to laziness on my part. The value proposition of this style, for me, was better awareness of my money (not a vague, "I have enough" or I have around $xxxx in my checking account and $xxxxx in my brokerage account).

However, there are tools to bring in transactions automatically and I did use them for a bit. There are tools that offer support for OFX, CSV, QIF and others listed on the linked page. I found OFX (not just with this, but in general) to be inconsistent across banks, and, when I did things "automatically", made it semi-automatic. I'd download the CSV of transactions and import them.