My 2 cents........I suggest reading the following link:
https://www.cnbc.com/2018/12/24/whats-a-bear-market-and-how-long-do-they-usually-last-.html
The above link indicates that worst bear market and recovery time since WW2 is 7-1/2 years or 90 months.
Do you have a rainy day fund that can last that long?
The second link on bonds during a crash is as follows:
https://obliviousinvestor.com/what-happens-to-bonds-in-a-stock-market-crash/
The above link shows that
some bonds can decline in a stock market crash...except for Government Bonds.
In general, most bonds do not decline as much as stock. However, certain bonds do decline and bonds can give you a sense of false security if you do not select the right type of bonds.
In general, Short term bonds are less risky than intermediate and long term bonds.
Total market bond funds co-mingle of short term, intermediate and long term bonds, government bonds, corporate bonds so a total bond fund may not perform as well as a short term government fund in a crash. In the long term, a total bond fund perform better than short term government fund but I don't believe that you can have both. (Safety during a crash and good long term performance)
You must feel comfortable with your portfolio having a sufficient safety net during a crash or bear market. Otherwise, you may have a hard landing.
I am retired and I have 7-1/2 years in liquidity consisting of short term government fund, short term corporate funds, money market funds and CDs. This is my safety net. The rest of my portfolio are in stock investment because of my safety net. If you have SS or other reliable income you can adjust your safety net accordingly.