The question at this point isn't really if you trade Scherzer (assuming he's willing), but when. The team is seven games under .500. They're under .500 at home and on the road and they're under .500 in every month so far. They're in last place. They are exactly where their run differential and other stats would suggest they would be.
In my mind, you wait until early July. If Strasburg and Corbin aren't both healthy and pitching well by then, you trade Scherzer ASAP, because the team can't get back into things without those two. The longer you wait, the less you get for Scherzer. At that point, you also trade anyone else whose contract is up this year who has any value at all: depending on production, that could include Hand, Schwarber (his 2022 option is mutual, so it's basically a nullity), Hudson, Castro, and Gomes. Some of those guys won't be traded due to suckitude: Castro, as of this moment. Most won't fetch much, but hey, the lack of good players is why this team lacks good results.
And then you hit the painful part. If Strasburg and Corbin are still useless in July, you have to ask the question of whether they will continue to be useless long-term. They're owed a combined $187 million over the next three years. Strasburg's exposure continues after that. At present, they are both untradeable. They will take up almost 1/3 of the payroll over the next three years.
Where I'm going here is the question of whether you also consider trading Turner especially, and also even Soto. My position would be yes on Turner. There is no reasonable prospect of this team being more than ok-ish next year even with Turner unless Scherzer or an equivalently productive player come back on an equivalent salary. Turner is making $13 million this year and will probably make around $20 million in his final arbitration year. He would get a lot more on the open market, so he has a lot of trade value. (Soto is a no for me just because of what it would admit: that the team is going to be very bad for four years. But it's close. The Strasburg and Corbin contracts are THAT bad.)
And the farm system is terrible. It's not just the worst in baseball; it's not particularly close to being not the worst in baseball. Besides Garcia and Kieboom (with all the bust risk there, he's still a reasonable prospect due to age), there is absolutely nothing above high-A that looks like a high-probability of being a major league player, let alone a good one. And even lower down, it's mostly lottery tickets as the only decent prospects who are even above academy/rookie ball are pitchers - and yes, spare me the Yasel Antuna bullcrap.
So you're either spending a ton of money on the major league level to fill holes you can't do internally, or you're trading guys like Turner so you don't need to do things like spend a combined $24.5 million to have a functional back end of bullpen and $13.5 million on replacement-level players at 1B and 3B. That's $38 million out the door on players that would take a team with a decent farm system maybe $18 million given staggered seniority. You gotta pay the bill eventually.