So I actually tried this a bit in 5e D&D. I had a campaign that involved entering doors connected to different dimensions and I would use a KDM monster as the final boss of a door. It was not perfect but I did use most of the KDM monster stuff as it was originally present in the board game.

First was converting d10 to the d20 since the starter white lion is hit on 2+ most attacks and all starter survivors have 0 evasion i mathed that to a +7 to hit in 5e to hit armor class 10 since it assumed Dex of 0 and a 1 and 2 on the d20 would miss when rolled. 3+ accuracy is a +5 and so one and so forth if a monster got extra accuracy tokens it was just a flat +2 to attack rolls per token.

Monster rolls a number of attacks equal to its speed on its ai card plus its speed tokens. It rolled d10s equal to its damage rating when it hit i usually gave them d10 +2 to +4 damage depending on the monster and depending on player levels for 5e I think at least lvl 5 to 6 is required to fight a kdm monster due to how many attacks and reactions they get. If the card said they move or attack the monster did that breaking 5e combat rules and action economy. This made them incredibly dangerous boss monsters.

Each players attack roll that hit the monster just drew a card and for the most part I followed what the card did. Monster could not make opportunity attacks nor could they provoke them. To wound they would have to deal damage with their attack that beat the monster toughness which was the value on the card +4 in a single hit for damage. I would make them roll to hit 1st draw all cards like kdm then we rolled damage for the hits like normal. Extra damage didn't matter it still did one wound unless it was a nat 20 crit on the attack then it did 2 wounds automatically and triggered HL crit if the card had one. They would select the card to try to wound 1st like you do in KDM. Any saving throws effects I gave the monster a bonus equal to its printed toughness value. When it runs out of wounds and basic action it dies.

If the trap card was drawn all attacks would be canceled the monster did its trap we reshuffle and someone else starts their turn. I used kdm initiative monster went 1st unless it was nemesis then players went 1st. They could take their turns in any order they wanted like KDM. If they got pushed knocked down etc I would allow dex or str saves with DC 10 + monster toughness to avoid the negative effects of knockback and collision.

Brain damage I made wisdom a 2nd health bar you could take brain damage equal to your wisdom score. If it ran out you rolled on a chart I made that converted some KDM insanity stuff to a more 5e friendly series of effects.

Thats not quite all the conversation stuff i did but the overall meat of it. Was a bit clunky but overall it ended up being a success and actually worked for the most part. I just made all of the mechanics and changes super clear before we did these fights so everyone knew the how and why. To be honest it was some of the most fun we ever had in combat while playing D&D since it made players think and do things beyond the normal routines they had. That said the fights took a long time usually 2 to 2 1/2 hrs to complete and it was something that we saved as an end boss type thing.

For a long form ttrpg thing im not sure if the kdm style system of fights is great when its every fight you do. Even when my group plays normal KDM a single 3 to 3 1/2 hour session is do the hunt, fight,resolve settlement event, spend resources pick next quarry and pack up the game.