A few months ago, an exploit involving wardens allowed players to gain massive amounts of MCMMO experience, particularly in Taming, Bows Tridents and possibly Unarmed or similar combat-related skills. Players used dogs to attack wardens, taking advantage of an unintended XP multiplier. This resulted in extremely fast and disproportionate skill leveling compared to normal or the default level up rate.

Issue:
While the exploit was patched (warden XP gain was nerfed), the levels gained through the exploit were never reverted.

Players who abused the exploit permanently retained boosted skills.

In the past, similar exploits (e.g., illegal Acrobatics farms in Dio and Alchemy haste potion bug) were handled differently, players who used the Dio's acrobatics AFK machine got their levels reduced and for alchemy levels gained through those exploits were reverted to fair values.

I believe the general nature of the server still relies on fairness, especially since MCMMO impacts PvP and other gameplay mechanics. Allowing exploited levels to remain:

This wouldn't be a issue if the current sieges were using wolves on a massive scale especially with the "Wolf Armor" update which came with 1.21.4
Here are some of the MCMMO abilities you gain by the time you reach level 1000:
Environmentally Aware (100+): This also allows your wolf to be immune to fall damage. It is a hidden skill that improves the usefulness of wolves drastically.
Gore (150+): Whenever tamed wolves attack a target, there is a chance that they will inflict a critical strike that applies bleed. The chance goes up 1% per ten levels to get a Gore, to a maximum of 100% at level 1000. This passive is extraordinary for PVP as it will deal 4 damage(2 hearts) to your target. This means that if you're attacking a protection 4 diamond armor player, 5 lucky hits will kill him. As your skill rises lucky hits will slowly become regular hits
Pummel (200+): When dogs attack there is a chance of knock back.
Fast Food Service (200+): Fast Food Service gives a 50% chance for your wolves to heal on attack, and to give you minor food.
Thick Fur (250+): With Thick Fur, your wolves take 1/2 damage and the plugin says that your wolf will get fire resistance but this is not true. Your wolf will just teleport to you if he was hit by fire or lava (bows with the flame enchantment and swords with fire aspect will not make your wolf teleport). The best skill by far when you want your wolves to survive.
Shock Proof (500+): Shock Proof causes your wolves to take 1/6 damage from explosions.
(!!!) Sharpened Claws (750+): Sharpened Claws makes your wolves deal an extra four damage per hit (2 heart). Dealing a total of 10 damage (5 hearts).

Here are two videos in both of which I am buffed with STRENGTH II attempting to killed the dogs with armor and the McMMO buff "Thick Fur":
https://youtu.be/V_zJV_OpcjU?si=WB6mj9320x07R8Lp
https://youtu.be/qircHup_ko8?si=_B2bQ9NzEbjHvTL1

What I'm proposing here:
Revert taming (and related) levels to fair values for those who exploited, similar to what was done for Acrobatics and Alchemy exploits.

Alternative:
If exact rollback is not possible, consider disabling Taming skills which are related to PvP (which definitely is not the most ideal but if players who obtained their XP with the exploit are to keep it then this is ideally the only alternative).