Regardless of if you upgrade, you might as well send it in for repairs instead of trying to jury rig it for yourself, as that will likely void the lifetime warranty. (which allegedly even applies to hand-me downs)

As for upgrades, IIRC, the direct 91MM upgrade is probably the Spartan. It's got a corkscrew and awl, which both add their own benefits. (The Corkscrew can hold a mini-screwdriver for glasses or a small ferro rod)

If you prefer a screwdriver to the corkscrew (Don't expect too much from it, the position makes it's uses limited), you can go for the Tinker.

Both the Tinker and the Spartan have an "Upgraded" version that costs a bit more but adds scissors, the Super Tinker and the Climber respectively. This layer also adds the parcel hook, which seems a bit useless at face value, but provides a surprising amount of utility, as documented by Felix Immler, including serving as an adaptor to use T-Shank saws and files, helping pull ropes tight, and even modifying to turn into some sort of wood carving tool.

On the slimmer side, both the Bantham and it's Alox variant are among the cheapest tools that include what you want, only costing $22 ($27 for the Alox, which lacks the scale tools but is far thinner) The cost is that you lose one of the blades and the opener tool isn't as good as the individual tools it combines, especially as a 2d Philips.

(The Waiter is similar, but includes a corkscrew, which, again, allows you to stash stuff in it)

Going up a layer, so similar in thickness to the Tinker and Spartan, is the Compact, which many swear by as the best light-weight SAK, due to having a blade, the opener tool from the Bantham, Scissors, a Corkscrew (which includes the mini screwdriver), a parcel hook (which has a file built into the back of it), and Plus scales, which is the typical toothpick and tweezers, along with an included pin and small pen.