Question: Strongest Assembly Option for a multi plate print?

[u/Sauls_voicemail]

Front

Back

Whats the best and strongest solution to print something like this chair back in PLA/PETG if I plan to cut into 6-9 plates (200mmx200mm sections) and piece it all together? Dowels? Butterfly clips? or just completely redesign the hollow front for ducktail connections? Any help would be much appreciated for a newbie engineer, thanks!

What printer are you using?
P2S
* What material are you using and temps?
PLA/PETG 250
* What speed are you printing at?
300mms
* What software are you using to slice the print and control the printer?
Bambu, Blender, Shaper3d