As always there’s no such thing as a global “best” application. Building your system is a very personal thing. It all depends on your needs and liking.
My personal journey in the tiling WM world has started 20 years ago with awesomewm. Then I moved to i3 because it feels lighter to me while offering a configuration approach I preferred. After some times, I felt ready to “really” build my tiling WM and I moved to dwm.
I couldn’t be happier until I came across bspwm which is as suckless as dwm but EWMH compliant. I also love the nice approach of keybindings offered by sxhkd. What I appreciate the most is the no limit configuration power since you can integrate the very powerful program that writes messages on bspwm 's socket (bspc) in any scripts you can imagine. This let you create some crazy and very personal rules. For example, I designed one where bspwm is listening to my video player state and if not fullscreen it automatically resizes it to a given size and moves it to a specific position. I have another one that will apply borders only to 2 specific windows applications and use a different color for each one.
This is a very brief overview of what I’ve experimented. Your expectations and the time you want to deserve to your configuration may guide you on another path. Archwiki has a comparison of tiling WM may be a good starting point to help you in your decision.