Titanium is not like steel, it has a very very week ferromagnetic response, which is why its used in surgical anchors and implants, it's MRI friendly.
There is a German manufacturer for ukulele steel strings, check for an US provider who sells Lenzner strings for ukulele, bouzouki, aoud, saz, and the like. String length is 615mm or 24.2". For steel strings on an ukulele guitar tuners are a better choice than the usual ones.
P.S. Once for a bariton ukulele I tried D'Addario's Single Plain Steels with g .012 c .016 e .013 a .010, but the Lenzner strings correspond rather to something like g .0085 c .011 e .009 a .007. They are even thinner, but .007 is the thinnest Single Plain Steel they sell.
I tried these D'Addario's Single Plain Steels with g .012 c .016 e .013 a .010 on an acoustic only ukulele with a 15" scale, but I didn't like the sound. Maybe that a somewhat tinier set sounds better.
Some nylon strings have a metal core that can be used with magnetic pickups.
The only nylon wrapped steel core guitar strings I'm aware of are Thomastick Infeld Classic S, but they only do the trebles this way..the lower ones are flatwound on a conventional steel core with silverplated copper windings. The other low-tension alternative is what is usually known as "Silk and Steel", steel core with a silk or nylon intermediate layer and copper winding, which are offered by several companies. I've used Silk and Steel strings on delicately built old parlor guitars, and only acoustically, not with a mag pickup. Neither of these types of strings are designed for use with magnetic pickups - I'd hazard a guess that you'd get some signal from a conventional magnetic pickup, but that's not what they were designed for, so if you go that route it would be a bit of an experiment.
By the way, the "titanium" uke and classical guitar strings are a bit of marketing hype, and it's rather confusing, and in my mind misleading. The name gives the impression they are made of titanium, but they are simply nylon with a titanium compound in them, so there's no titanium core or wrap. The "titanium" guitars strings are only reinforced with a titanium wrap at the ball end of the string.