copied/pasted for length

The third thing actually kind of nullifies the second almost, and it's that if you struggle with rng control with two dice sets rolled against each other for robbery, you can easily reduce that to one. Instead of a roll, give each property a target number to reach and the player simply rolls the movement dice to check to steal. This way, you can have far more control over thievery odds, rolling low on movement is no longer a huge disadvantage in multiple ways, and you can make the progression match that of an original monopolu board (3/4, 4/4/5, 5/5/6, 6/6/7, 7/7/8, 8/8/9/ 9/9/10, 10/11 (or with enough rng boosting cards or effects at a player's disposal, 11/12)). Again this way, you have target numbers right on the board rather than a difficulty rating and a target number or target dice, which cuts out not one but two middle men.

Good luck with the project and all. I might take a closer look sometime, but it's kinda late right now to be honest.

I would advise three things, just by reading the description on this workshop page.

Firstly, remember that rolling multiple copies of the same die is possible. If the d12 and d20 are giving a lot of variance, you can easily change them into bell curves with 2d6 and 3d6, and though 3d6 can be a challenge, it's more reliable to at least be below 12. As a side effect, it also means players get to roll more dice, which is a plus, and that less types of dice are needed for the game, also a plus.

The second thing I would reccomend is to print the dice required straight onto the board along with each property. If all cards or effects that interact with dc instead read "property with a difficulty of 2d6 or less", you could even remove the difficulty number entirely. Less things to check, less rules to try and memorize, far more straightforward casual gaming experience.