My suggestions is one of this:

Mac Mini G4 1.5 HGz / 64 MB VRAM ( i.e. Silent upgrade )
+ small, nice, low consumption, easily overclockable to 1.8 GHz
- old graphics card gen.R200, only 64 MB VRAM, only 100 MbE, ATA100 HDD, not expandable

Powerbook DLSD/HR - Al G4, 1.67 MHz / 128 MB VRAM
+ portable, decent 128 VRAM, 1GbE
note: graphics gen.R300 is better than Mini has
- ATA100 HDD, native resolution 1680x1050 or 1440x960, not expandable

iMac iSight G5 2.1 GHz / 128 MB VRAM
+ all-in-one, lowest consumption from G5, SATA 150 HDD
note: graphics gen.R300, better than Mini and Powerbook
- not expandable, native resolution 1680x1050, not as fast as should be according to CPU frequency ( faster than Powerbook 1.67, but slower than AmigaOne X1000 1.8 - benchmarks from 2020 )

Powermac G5 2.7 GHz Dual Processor
+ MorphOS fastest
Note: should be used for linux, I have no experience
- terrible power consumption, old type water cooling, PCI-X + AGP bus, i.e. older graphics cards, I not have one

Powermac G5 2.3 GHz Dual Core
+ PCIe bus i.e. more modern graphics cards, expandable, one of MorphOS fastest
Note: should be used for linux, a little bit slow
- I not have one

Powermac G5 2.5 GHz Quad Core
+ PCIe bus, expandable, one of MorphOS fastest
Note: should be used for linux, decent speed
- terrible power consumption


Most often I am using my Pegasos 2 ( 1.33 GHz, Radeon 9800 Pro, SATA ). And sometimes when I need most power, I switched on G5 Quad.

And back to initial question: Mini 1.25 GHz I cannot recommend becouse of 32 MB VRAM. Powermac G5 2.7 GHz has most problematic cooling from all Powermacs.
If I want today buy "new" MorphOS machine, I will select one of this:
Powermac G5 Dual Core ( most modern, expandable), Powermac G5 Quad Core ( most modern, expandable, linux), iMac G5 ( small ), or Powerbook ( portable) depending on your needs.

[ Edited by sailor 28.11.2023 - 10:35 ]