Any thought would be appreciated as I'm having a hard time of what to do with the "paper gains" of the past 9 years.
I'm going to FIRE within 2 years [most likely] and I am 100% stocks. This is not to suggest you should be the same, but with a 10 year investing horizon you have to ask yourself what does going 40% bonds do for you? What actual situation do you foresee in your life would be different if you made that change?
For myself I am staying 100% stocks because there is no amount of bonds I am realistically going to hold that would mean I would decide to FIRE right into a major market crash. If I was 100% stocks or 80/20 or 70/30 doesn't matter when the market crashes 30%-50% I am not going to feel good about retiring and I'll keep working...perhaps just part-time, but I won't start living off my portfolio anyways. So moving to bonds before I FIRE seems pointless to me - especially with every central bank talking about raising interest rates.
When I am ready to make the irrevocable decision to FIRE [ie. give notice] I'll switch to some bonds/cash to get me through the early sequence of returns risk period, but I am shooting for 15%-20% at the most and I won't add more money to that asset class if I either use them to live off of or if my stocks outrun them.
Again not suggesting this ^^^ is the right plan for you OP, but I do think you need a specific plan that makes it clear why you are holding bonds, how much to hold and the pros/cons. Just moving to bonds as a reflexive "safety" move does not seem smart. Using cFIREsim you'll see a high bond allocation lowers your success rates for long retirements.