Zilents are basically Zealio V2 with some dampening added.
They should be as tactile as regular Zealios, except insofar as the dampening may reduce tactility. But they are just dampened Zealio V2, for the most part.
And yes, they are some of the most resistant silent tactiles currently available.
If 78 G are not available, and only 67 G, that’s not a big deal. You can always put in your own 78 G springs later. Lubed aftermarket springs are probably superior to what Gateron [Zealio manufacturer] are using.
Again, the classic heavy tactile with smooth action and stiff spring is probably the earlier-mentioned Gateron Kangaroo Ink.
It’s a heavy-tactile like Zealio V2, but with a weird 2-stage spring that makes it feel different on the upstroke. It’s also an Ink switch, so it may already be pre-lubed for you.
The KTT Matcha / Carpinteria is a pretty stiff medium-tactile that could likely take a more powerful spring. Matcha is available on AliExpress, but overall this probably isn’t one of the most available switches in Europe.
If U4 or U4T Boba are available in Europe, that housing should be able to handle at least 78 G. Use the stock U4T and heavy-spring it. Or put any Panda-like stem in any Boba tactile housing, and use a heavy spring. Should be top-mounted tactility. You don’t need to lube much with these, just the spring and parts of the stem. Easy.
If JWK / Durock are more common, you could get a Durock Midnight, which is a medium-tactile stem inside a T1 housing. (Or just make your own.) Put a punchy spring in there. With a 22mm heavy spring in there [I know they will fit in Durock Medium Tactile], it would be hard for me to accidentally depress the switch.
EDIT: The Midnights you could get or make today may not be as punchy as the original, so better to try Boba first, if available.