To be frank, there are plenty of low-hanging solutions, albeit not with the current roster. Servants like Medea or Gilgamesh can undoubtedly solve the problem with ease. Remember, Medea is canonically on par with a true magician, and with divine words it would be easy as could be. Or, hell, if any Artoria was summoned and canon Shirou was summoned to trace Avalon it'd be an easy fix, albeit the low chances of that happening.
That's not to mention that Chaldea literally summons outright gods, and beings that control death/souls like Ereshkigal could do something. That's not even mentioning the gorillion grails they acquire that could probably fix it, since grails were created on wishcraft, which is capable of anything with sufficient mana, given they can rip a hole in the fucking Root. Fundamentally, it isn't a problem of fixing her body, which is replaceable, but fixing her soul. Wth the resources available, while it's tough to do so now, with many Servants it'd be easy to either extend her lifespan and find a better solution, or fix it entirely. Illya and Miyu both work too, with dress of heaven, wish-granting, and Ruby/Sapphire pulling a fix from parallel worlds all are ideas. Hell, Solomon/Romani might have some ideas himself, and has the motive to tell it, since he greatly cares for Mash.
The third true magic would definitely fix it with ease, but it's not needed. Soul-depth immortality, which is essentualy preventing the degredation of the soul is a dime-a-dozen for Servants, and precious materials and knowledge needed to do so are very much gatherable in singularities, since they're almost all in the Age of Heroes/Age of Gods, as do most of the Servants originate from those eras. In the AoGs there were basically no limits whatsoever in any magic, and yes, it was magic.
But yeah, modern magecraft won't help too much, barring very specific people.
Aside from that, here's hoping Taylor gets Zolgen's shit, the worlds get full lol-tier by Babylonia, and it seems they're starting to summon people that are just better at everything Taylor already does right now, making her even less useful in general, and likely relegating her to canon Ritsuka's role of just existing. If a baseline normal human Nero, an empress, can in a singularity grab her sword and exchange several blows with a top-tier Servant and use her NP, which happened not too long ago, so should Taylor be able to do something similar by the end of the entire Human Incineration Incident. I'd like at least one low/mid-tier Servant dealt with by her by then as a landmark for her growth. Maybe Shakespeare can make her some more stuff by telling him more of her past?
Aside from that, I'd generally like her past to come out at some point.