"AP"
Believe it or not, Gardevoir likely doesn't have an AP advantage here despite Renamon's lack of a "+". Renamon can stomp Folder Continent Digimon easily. Folder Continent Champion level Digimon are so much stronger than the File Island Digimon (Seadramon who performed the feat) that the File Island Digimon can never hope to compare.
And as I've said, Renamon has effortlessly killed multiple Folder Continent Champion level Digimon by herself.
"Versatility"
Gardevoir is not that much more versatile. Honestly if we go by most dangerous abilities, Renamon is more dangerous overall.
Clairvoyance and Precog
I assume Future Sight and maybe Detect? It isn't passive, she has to activate this ability.
Telekinesis
Dangerous, but it is by no means a game ender.
Healing
Renamon can do so as well.
Teleportation
Renamon can do so as well.
Illusion Creation
Where does this come from?
Sleep Inducement
Both can hypnotize each other. Renamon can literally trap her into a nightmare directly.
Power Null
So Kohenkyo, Cat's Eye and maybe Nightmare Shock.
Small Black Holes"
Drains all her power as such if it misses, she's up a creek without a paddle.
Spatial Manipulation
Dunno how useful distorting dimensions are. Especially when Renamon was around Megidramon who was doing the same and also destroying them passively.
Life Force Draining
Renamon can flat out rip her essence out of Gradevoir's body. Also she can do the same via Demi Darts.
Plant Manipulation
Leavez for dayz.
Stat Amping
Overwrite covers that. Not to mention this hurts Gardevoir as all it takes is a Digi-Modify: Poison to turn all that power against her with even more potency and destroy her from the inside.
Duplication
Both can do this.
Forcefield Creation
Sharp Wing arguably bypasses this.
Who wins in my opinion you ask? Neither. It's a tie while leaning toward Renamon due to many more skills that can one shot Gardevoir. However, Gardevoir also has some deadly skills of her own.
Inconclusive for me.