True, but I don't think this guy is a coin flip. He's been heavily scouted, in a way MLB was not even close to back when most of those players (besides Ohtani) came over, plus he's faced MLB players, and he's only 25. Some teams may not want to pay him at the top end because he's not a sure thing (and smaller physically) but he's unlikely to be a bust. Worst case you are overpaying for a third or fourth starter but he's as likely to pitch for 10 years as any other guy.
The downsides of him as a player coming over from Japan far outweigh (IMO) the ones that Snell or Montgomery come with (whether that is QO compensation or the actuarial table), plus his AAV will be lower (with the posting fee also not counting against the tax).
I don't think he's a very likely guy for the Phillies regardless, they got Nola, and they'd like to keep Wheeler. But if we're contemplating the team doing truly insane or dramatic things (just for fun!) signing Yamamoto would also be the way to trade your young pitching for Soto (at least Abel if not Painter) and then if they wanted to keep Soto they could cut Wheeler loose when his deal is up.
A lot of Twitter talk about including Bohm in a Soto deal, as if he'd make a difference one way or another (for either team).