I'm not doing the full on debate as I'm leaving that to Ant.
But in summary:
Filoni credits Maul for doing well beating Kenobi in Revenge due to the major disadvantages Maul faced. He says Kenobi couldn't win because he was in the wrong mind set. End of.
Filoni acknowledges Maul was still majorly disadvantaged in Revival. He says Maul, then later Maul+Opress couldn't defeat a Kenobi in the right mind set especially after the extra boost of focus he reached after Adi's death.
Given how clear Filoni made it that Maul's velociraptor legs limited his mobility, it goes without saying he'd be Even More limited in a cave environment. Yes Kenobi had the disadvantage of being outnumbered. But I don't accept his fighting style was a disadvantage. He seemed to mix up the best of all his combat moves, and Filoni pretty much confirmed that was a peak performance for him given his intense level of focus to right the wrong done to Adi.
It's funny how you always mention your favorite characters are pre-prime, but ignore that their opponents are as well.
S4 Savage was Pre-Prime, given he hadn't been trained by Maul yet, and Dooku even points out he's gaining power every day. Not sure how you decided S4 Ventress was pre-prime, but alas given Savage was pre-prime it wouldn't matter.
Likewise S5 Kenobi was pre-ROTS prime I guess, though I'm not sure how much he improved from S5 to ROTS in Canon. But Maul was still in recovery in S5 as per Filoni. So of course he was also pre-prime. He was gaining power (as noted by Savage), he was still in recovery, and his more human sized legs would allow him to properly utilize his acrobatics and martial arts (essential part of his fighting style) as confirmed by Filoni.
I also find it amusing how vague statements by Filoni, which are not clear cut or expanded upon at all, are treated as word of god by you in favor of your preferred characters, but his more clear cut statements in favor of characters you argue against are almost brushed aside by you.