I tried looking around but i just cant seem to find the answer for this.
There are two ways to get upgrade points.
1) Do the Main quests. If you do the quests for the mage's guild, you get points. about 10-15 per, I believe.
2) Sell slaves. The better the slave's rank and stats, the more money you get. But you also get upgrade points for high rank slaves.
These are the only ways to get them. It's a little grind-y to get a decent number of 'em, but given time, you can get as many as you need.
hey idk if the creator of the game reads this or not but they might want to put a button to add U.Points into the game in sandbox mode or just give the player X amount when starting out in sandbox mode or at the very least have all the upgrades already unlocked lol though this is more of a suggestion than anything but you might want to look into it though in any case