"Yacht rock" is such a fungible term that it's probably not worth binning until people are certain they're using the same definition.
That said, I'd loosely divide Toto's phases like this.
First four albums (1978 - 1982)
Fusion, which often fits comfortably in a lot of people's definition of yacht rock. Lots of pop-rock melded together with R&B of that era, which now often retroactively meets people's criteria for yacht rock. Though even there you run into songs like Hold The Line which are just straight rock anthems.
Next three albums (1984 - 1988)
Sharp turn into 80's pop-rock. Sometimes powerful and anthemic, sometimes ballad-y, sometimes strange (think Mushanga), but definitely closer to the quintessential 80's pop sound, and gone is the lingering impression the previous albums left you with that they were all secretly sneaking off to listen to Motown records.
One-hitter-quitter compilation phase (1990)
Columbia Records releases a greatest hits album featuring four new songs that sound......pop, but not like the previous pop sound. More in line with the slightly edgier, updated pop sound of the early 90's. Something closer to INXS than Tears for Fears. Lots of fans don't like it, singer gets booted in short order, it doesn't last more than that. I kinda dig it, though.
Regular rock (1992)
Album sees the end of hiring the rafter-piercing front-men required for the 80's, and guitarist Luke just sings the whole thing himself with a pretty good straight-ahead rock voice. Gypsy Train I posted is par for the course on that album. By that time Steve Porcaro has left the band and taken his mountain of synths with him, and that lacking influence is vividly obvious.
Some kind of prog-rock and pop blend (1995 - 2006)
New drummer Simon Phillips drags the band relentlessly into prog-rock influences for his entire tenure. The final album in 2006 is so prog and weird that even I don't like it. The early offerings are still really cool, though. Even though prog is not my thing, their pop sensibilities gel it into some very listenable stuff. Band continues until a hiatus in 2009, but 2006 is the last album.
Back to pop-rock, but disjointed somehow (2014 - 2020)
Prog drummer out, the next albums return to sounds which are kind of similar to any and all of the pre-prog phases, but the albums feel fragmented, like each member is writing the songs on his own and then they're all thrown onto one record. Which is probably what happened. Steve P. is back, and so are some of the synths. They're also getting old, and the inability and/or lack of desire to absolutely blister crazy-off-the-wall solos is noticeable. Still a bunch of good songs, even if they don't necessarily flow into a coherent album.
And that may be it for recording. They still tour, but lost a lawsuit a few years ago to Jeff's estate, which they said makes it financially implausible for them to record any albums using the name "Toto," and they're not willing to try to re-brand at this point. For a while they claimed "they couldn't afford to play any songs live that Jeff co-wrote" including Africa, but I suspected the fans would demand they find a way to bring that one back, and I notice they have. From the interviews I've seen, they're not optimistic about any future albums.
