The key here is that different aspects of Fantastical can be configured to see different calendar sets. E.g., you can set your lock screen widget on a particular focus mode to show only the meetings, and so on for every place Fantastical shows up on your devices.
I have one time blocking calendar, and a few events calendars describing the hard landscape. I schedule one to four 1.5+ hour time blocks per day depending on the day. The key for me has been locking down distractions pretty harshly during those blocks. I started this practice a few months ago and have been loving it.
I have been using a few other utilities to help with this:
Rules triggers different Shortcuts depending on the event coming up. I use it to switch focus modes, minimize everything, and lock down distractions. (I actually talked about this one in the last segment of my recent chat with David!)
Dato provides a customizable menu bar display of upcoming calendar events. It also has a feature where it presents a big full screen notification/reminder of particular kinds of calendar events. I use this to warn me when a time block is about to start. (Dato is on SetApp.)
Ultimately, though, Mike Tyson’s classic wisdom holds true. My days often see me getting punched in the mouth (though my toddler has yet to take this literally), so the plans go awry. Reflection is key (as @KVZ put more eloquently). I’d add that forgiving yourself and trying to be the sky, not the weather, is usually central to my reflections.