Look at the MtG world pre-nerf.
Urza built a school to train and research to battle the BBEG.
Teferi became a court mage, an entertainer, all while covertly leading his nation to new heights.
Commodore Guff was building a library that contained all knowledge in the world.
Bo Levar was a interplanar smuggler and he liked his job.
Freyalise created a huge enchanted forest and the entire eco system within it, then defended it.
Serra took creation one step further and created her own imperfect plane based on her 'divine' beliefs.
Karn did better, his mechanical plane requires no upkeep and is apparently self sustaining.
Nicol Bolas has never stopped seeking power.
Sorin ended war on his own plane, then stopped a bunch of world eaters, even depowered he still seeks to maintain balance.
These people are like average joe acquiring the Paragon Template and 30th level Sorcerer Spellcasting. They can go anywhere, cast any 'mortal' spell, effectively immortal, and so on. Like Bo Levar walked to the bottom of the ocean and grabbed a square mile of water and transported it on land flooding an ungodly sized region, effortlessly. For the most part, the continue being exactly who they were to begin with but a few turn to building the perfect society in their own image. Like, got a social loving Sorcerer who loves whores and drinking? He is probably an interplanar pimp using Summon Monster in fun ways. Got a Cleric that upholds Pelor's ideas? Probably creating a one church based city or fulfilling 'pope' duties. Etc.
Also, no matter how powerful you are someone is always bigger and badder (either mob, god, or you but +5 levels). This is especially true when talking about TO paranoid Wizards since they live in a continuous state of fear for death or showing a weakness against unknown threats, their lives are dedicated to living in a very complex living tomb.
