Created attachment 165707 [details]
demonstration of the issue by drawing a square on each monitor

SUMMARY
Incorrect graphics tablet mapping with multiple monitors with different aspect ratios, when tablet area is set to Fit Output in tablet

STEPS TO REPRODUCE
1. Plug in multiple monitors with different aspect ratios
2. Change "Input Devices > Drawing Tablet > Target display" to "Follow the active screen"
3. Change "Input Devices > Drawing Tablet > Area" to "Fit Output in tablet"

OBSERVED RESULT
The tablet area for all monitors is the squished/stretched into the same tablet area as the primary monitor (e.g. if the primary monitor is 21x9 and the secondary monitor is 16x9, the tablet area of the 16x9 gets squished vertically to fit into the 21x9's tablet area)

EXPECTED RESULT
Each monitor gets their tablet area determined independently (21x9 monitor gets a 21x9 tablet area, 16x9 monitor gets a 16x9 tablet area)

SOFTWARE/OS VERSIONS
Linux: 6.7.4-zen1-1-zen 
(available in About System)
KDE Plasma Version: 5.27.10 (Wayland)
KDE Frameworks Version: 5.114.0
Qt Version: 5.15.12

ADDITIONAL INFORMATION