I have also thought about this, and it's an easy rabbit hole to fall into. I'm all for more variety, but you have to cut it off somewhere. You also have to be careful to not trivialize existing skills in the process.
Without going down an endless rabbit hole, there are two new methods I would be in favor of. One, as you mention, could be a strength check. This could scale with the required lockpick / hack to open.
Another one might be sacrificing a grenade to try and blow the container open as sort of a last ditch effort. Though something like this is prone to abuse by save-scumming.
Someone, and I apologize for not remembering, in the discord suggested the query of what if there were explosives in the container? I argued, why not, part of the benefit of having something like lockpicking or hacking can be that you don't have that kind of a risk. A major benefit of taking them as skills is that they're not only stealthy, but far, far safer than their alternative options. An explosive entry could detonate something and blow up in your face, an electric one could fry you alive like a downed power cable, chemical could destroy the container and leave it as a giant sputtering puddle of acid.
There's a lot of ways you could theoretically balance the alternatives to make them not so clear-cut appealing. They exist in my hypothetical mind more as ways to diversify builds and allow more interesting interactions with the world than they do to remove the power or validity of lockpicking/hacking.
It is an interesting way to allow for build that do not take lockpicking / hacking to still have a go at it. But again, you have to be very careful as to not step on the value of those skills in doing so, which may be impossible. If you allow the player to still open containers without having the appropriate skill, you inherently diminish the value of that skill.
Lets say for example that a crate needs 100 lockpick to open, but I don't have a single point in lockpick. I decide to use a carefully placed grenade to blast it open. Unbeknownst to me, the crate contained a cache of MK III Plasma Grenades and I get turned to ash. Let's also say for argument's sake that for any given lockpick / hacking requirement, the difficulty of "forcing" open a container increases.
So, for the 100 lockpick crate I just mentioned that difficulty might be somewhere around 30% chance to open, with the other 70% being that the contents of the crate are destroyed. For the more difficult hacks and lockpicks (130) the fail percentage could be as high as 95%, or maybe more.
HoweverAll of this is meaningless due to the nature of the game. What is stopping me from reloading over and over again until I don't fail? By doing this, it is possible I open every container in the game without having a single point in lockpick or hacking, rendering them worthless.
You can say "Well then just don't abuse it" or "People won't do that". While I personally would not abuse it, the fact of the matter is that it opens the avenue to cheesing all containers and making two skills useless.
The
only way to stop this would be if Underrail pre-rolled all your chances the second you started a run. Even so, you still get to open containers you otherwise would not have been able to, diminishing the value of lockpick / hacking significantly.
With all of that in mind, I would not be in favor of a system like this unless Underrail got a complete overhaul in how it handles lockpicking / hacking and save-scumming.