The Cubs averaging 5 runs a game in the Giants series, after averaging 5.3 runs a game in the Brewers series, after averaging 6.6 runs a game in the Pirates series, is technically yes trending down, but not at all portending a 'slump'. 5 runs a game gets you 810 over a season which would have been fourth in baseball last year. We were hitting at a borderline historic pace for the first month or so of the year (123 wRC, which would have been second best of any single season team in baseball since 2020). It's coming down to 'just' being a really good offense and we're having grouping/timing issues. It happens.
To 1908's point: it's absolutely going to get worse than this. And that's fine, we had a really strong start and we have a really good opportunity coming out of the Mets series to pad the record (Miami, CWS, Miami, Cincy maybe without Hunter Greene, Colorado, Cincy, Washington). We need a starter, maybe two, and we need Shaw to provide some consistency at third (even if it's not a bunch of excess production). But I think the offense alone gets us to 85 wins and I think that probably is enough to win the division, so we have some cushion to identify the needs and the best solutions to optimize getting beyond just a playoff appearance.