Well written thoughts! I've definitely shared many of your feelings more times than I would have thought at the start of my long career.
Corporate jobs disappeared due to the financial crisis one time and a hostile takeover another time (both of those I was personally happy about). And a couple startups were acquired sooner than expected. There can be upsides, yes, but it can still leave you with months of trying to figure out what to pursue next, and that can be a weight on your mind even when you're making the most of your time off. When you are committed to a full-time job, something you have to do every day, you may dread going to work sometimes or just wish you could hike up a mountain or something, but it helps frame your day and reduce the number of decisions you have to make, so when you don't have that there can be a significant cognitive load trying to decide how to spend your time in a way that others may not understand. "Oh, that's nice, you're consulting, how flexible, lucky you!"
Early in my career I learned about how to come out of the gate blazing fast since when I graduated from college a couple decades ago half of the tech jobs were gone, and I had to work hard for months after graduation just to find a specific kind of application development work I wanted at the time. I was fortunate to find that but many others were not and had to take whatever came their way. But it wasn't easy, and like you said, I found out early that lots of interviews on your calendar isn't necessarily promising, so over the years I've tried to find alternate routes to work by meeting with people inside the company first to find out what it's really like, and how much they want to fill a specific position, etc.
And more important than all the above, I recommend finding a listening ear to share your journey with, someone who will try to understand where you're at! I have some friends who have had the same job for a couple decades and even though they may not relate well, we can still try to share our different lives with each other and it's more helpful than you might think!