The second ability would be fine on its own, but combined with the other one it means that strength-based melee characters (the aforementioned barbarians, fighters, and paladins) barely get to play the encounter. While there are more ways to make saves as you level up, when the DC is 27 you'd better have proficiency in that save or you literally can't make it. There is no way to boost all of your saves that high in 5E. DC 27 is just "if this isn't one of your class stats, you fail". Especially when the paladin buffing your saves is one of the most likely to have been teleported 90 ft away last time.

If you're the fighter in plate armour, well either have fun spending every other round dashing back towards the fight and not hitting anything, or have fun feeling like a liability because the casters have to keep spending their turns and resources just to get you back in the fight. And you'd better have 20 ft of movement left if you actually do hit it too, which you don't because you only just made it back into melee. It feels like the entire encounter is telling you that you're an idiot for wanting to play a guy in armour.

Obviously if you find it fun, I'm not about to tell you that you're wrong to do so. That's just subjectivity for you, as you said. I do think it's good for monsters to counter specific classes sometimes, but when it's something like Goxomoc, which is two CR 30 creatures in one, that's basically the only thing you're doing that day. Being hard-countered all day is just not playing.

I agree with you that 5E's tarrasque is dull. Personally my go-tos for fun high CR statblocks are Fizban's greatwyrms and Glory of the Giant's scions. They've got all sorts of nasty abilities. They just don't feel like they're laser-targeting specific players in the party, and the harder control effects are typically slightly more avoidable with proper tactics and builds.