Magery Unlock works on lower level locks/containers. It is scaled with your magery skill. Personally I do not think it is worthwhile to have 120 magery to unlock some containers, when you need 80+ lockpicking to open the rest.
I would script for LP skill to open chests.
If your character is dedicated to this task, then maybe your template wouldn't require GM Lockpicking. I generally top of the skill, so if I want to use it for t-maps I can - even if I have to soulstone around some other skills.
If you have the available template points, I would consider the dungeon artifact/chest thief: stealing (120), remove trap, lockpicking, magery/chivalry (65?), hiding, stealth (85?). At about 570 points you could roam almost anywhere. I have used GM hiding/85 stealth to explore every dungeon with low 90's magery (maybe 92? = 100% success level 6 for invisibility). After casting invis, immediately I start walking a few steps to avoid the auto reveal by monsters. That is approximately a 602 point template. I equip some +skill items to help it along.
Easy to get another 200 points in there toward some offense, whether it's Eval + Meditation or Melee/Tactics, or even increase magery, add a mage weapon for some basic offense/defense. I tend to do a repeating xbow, mage weapon with spell channeling and HLL. Lots of functional options for visiting more dangerous places outside towns.
A full resists suit with MR/LMC - so no need for meditation if you mana pool is high enough.
That is my COVID-19 ramblings...
Gaderian