Go to baseball-reference.com, search on Kyle Schwarber. Select "splits" then "2023." Among the splits are the last seven, fourteen, and twenty eight day totals. Schwarber's OPS for past 28 days is .691, which is in fact "struggling." Moreover, his 14 and 7-day splits are progressively worse, suggesting that it's been getting worse, not better. We can hope that the All-Star break, and (depending on Harper) perhaps more time at DH, will help turn this around.
Stott's splits are a bit more mixed. His OPS on the season is .753. The last 28 days, it's .852 (good!); but the last 14 days, it's .712, which indicates that he hit a rough patch in the last two weeks. But then, in the past seven days, his OPS is .891, which is really good. Suggests that the past week was good, and the week before that (when he had 16 PA in four games) was...well, BAD.
All these monthly and weekly splits are, necessarily, very small samples. Things don't even out in a week, or even in a month, really.
On the subject of leadoff... Stott's OBP on the season is .333; in the last 28 days, it's .329. Schwarber's OBP is not good - not on the season, and not in the past month (.316 and 287, respectively).
Schwarber has hit leadoff in 36 games this season... to an OPS of .714, w/ an OBP of .287.
Stott has hit leadoff in 38 games, to an OPS of .650, w/ an OBP of .297.
None of those numbers, in either case, say "leadoff hitter" to me.
Of the "qualified" starters (based on innings), Stott ranks fourth on the club in OBP, behind Harper, Marsh and Castellanos; Schwarber ranks sixth (Bohm is fifth). On OPS, Stott ranks sixth, Schwarber seventh.
Given their on-base percentages, and their overall roles in the batting order, I might suggest that Brandon Marsh should lead off, with Stott in the two-hole, followed (in some order) by Castellanos, Harper, Realmuto, Bohm. Schwarber, Turner and Sosa should bring up the rear, until such time as their hitting comes around and earns them a higher slot in the order.
