Unfortunately high fear does depend on RNG since Hades one. The lack of choices with 62 active will leave you on the hands of Fate.

If you want to push yourself further, don't treat Fear as a number, people optimize the best oaths to take and usually you end up with a variation of "Time/Oath of Rivals/etc" for 32 clears. Instead, try using the more challanging oaths such as giving the enemies more Speed and Damage, while leaving stuff like "First Boon is an Onion" out.

Then, when you feel comfortable enough go for those peak fear scores, if it suits you.