I'm a big fan of the FR1Mk3F. So are you. I don't know the Eroica, neither do you. To buy an Eroica, and leave your FR broken, is taking a big risk on the unknown. (You've presented it as an either-or; if you can afford both, it's a different calculus.)
And all we're talking about is a "tip profile". The Gyger is fancier than the FR's line-contact, but it's the same principle — is the Gyger that much better? I already have the Gyger tip, and it's brand new — on a NOS Ortofon MC30 Super — and it sounds like crap, dead, dull and lifeless. Can't be the tip, though, must be the cartridge, because the tip sounds great on a different cart, N'Stein's Eroica.
As Mr Pig wrote so wisely in #101:
"Perhaps one issue that is not being addressed is the hierarchy of elements within a cartridge. Not every aspect of the design is going to contribute equally to the end sound. Also certain factors are going to create a hard ceiling, and improving other aspects such as diamond or cantilever may have minimal or reduced contributions to improved sound. So many of these aspects are unknown to the general hobbyist, as cartridge manufacturing tends to be a bit of a black art. What is more important, coil winding architecture, magnet materials, magnetic gap, application of damping materials, suspension materials and architecture, chassis resonances, coil wire characteristics, and so on and so forth. And which element creates a hard ceiling for what level of performance that can be attained? We really only can change one or two things about the cartridges we own during the retip process."
If you're very intrigued by the Gyger, retip the FR with one. You know what all those other design attributes deliver with the FR: amazing sound in every respect. The Gyger certainly won't ruin it, probably enhance it. I'm lucky, I have a couple spare NOS FR1's warming the bench, and two more in play on TTs, still going strong. So I don't see myself retipping any of them — but if I did, I'd be sorely tempted to try the most advanced stylus geometry available. Benefits over the very good original line-contact might obey the law of diminishing returns and merely sound amazing — but they might produce utter magic.