feel like this roaming issue is viewed in a reductionist way too. the context of ten haags words, for example, were an evaluation of how to get the most out of Frenkie. it wasn't his point that Frenkie can't play as a six because for some reason, you can't tell him not to roam around. it's his point that if you wouldn't utilize his roaming ability in a six position. it's not like he just violates tactical instruction. ten haag putting him in a double pivot was a way of building the team around him, getting the max out of him because he was their best player.
of course there are ways to moderate it. you don't have to accomodate him fully with another pivot. but you also don't need to have him stuck completely in the anchor position. the ideal is a fluid trio who can cover for each other. if this wasn't Xavis idea, he wouldn't have Gavi press as an attacker. what's the point of an achored dm if he's isolated when the pressure lines are broken? offensive football requires courage to roam and vacate your base position.
there were periods under valverde where Frenkie was stuck in this weird makeshit LM. he took on that role even though it was against his natural instincts. of course you can mold him. of course you can school him as a classic six. of course you could instruct the midfield around him to cover when he takes a stroll.
and don't tell me that Busquets himself didn't roam much more in 08-11 or in Lucho's first season.
What's the point in instructing him not to leave his position, if what you get from him as a 6 lone pivot is something meh at best, and hampering the team at worst??
It's not about being a static anchor. It's more about the skillset we discussed: positioning (Frenkie is not good), knowing when to pass/release, and time on the ball - releasing first touch to the correct passing lane (Frenkie is bad there too)
Busquets never roamed in the way you imply. That's the thing. He as one of the cleverest youngsters ever in a position that requires brains, and that showed in his positioning and impeccable decision-making in regards to when and where to pass
The only viable solution would be to change everything to accommodate him, like Koeman wanted to, and play him in his best role with another DM next to him.
But if Koeman himself abandoned the idea, does it mean then that what you get from accommodating him is not worth all the hustle?