If you go to userbenchmark.com you can enter the name of any Optiplex that interests you and see what CPUs are being used, and a performance ranking.
Almost all Optiplexes have a 95W CPU limit. The newer ones get more performance out of that 95W than older ones.
The Mini Tower versions are the only ones that support full height GPUs, and aftermarket PSUs.
Up to the Optiplex 380,780,980 models they were BTX format. The Zotac GTX1050(Ti) Mini is the only 1050 that fits.
Many newer Optis have a proprietary 8 pin connector instead of the 24 pin ATX MB connector. There are adapters for this. Due to the 95W CPU limit they stilll use the 4 pin CPU connector and almost never have a 6 pin PCIe cable on the PSU.
The PSUs are quality parts and the seemingly small power rating is due to the 95W CPU, and the small number of expansion slots and bays they need to run. They're designed to power every slot, bay and CPU that's available. Parts like GPU,RAM, and SSD can be moved forward to your next computer.