By any reasonable definition of 'tanking', the only player on a multi-year deal that would qualify at the moment is Swanson, and he also has battled injury and has a long track record of consistency while only being 30. If the team plays like they have for the last several weeks indefinitely, they'll be quite bad and be in an uncomfortable place. There's no indication that's likely though. They've earned their full-season record to date, though there's reason to think that's below their true talent level. At this stage in the season, the difference between a 75 win pace and a 90 win pace is a handful of games that randomness is going to play a large role in influencing.
I don't want to imply there's zero things to worry about though, while I don't at all believe the team is screwed for the near term, these are the things I'm concerned about:
The Catching position, today aside I'm not worried about Amaya as a receiver, but the bat and running game control haven't been good enough, especially since he's had to carry Gomes being a large negative everywhere but game calling. The options on the market aren't ideal, and making a change at that position carries a risk for the pitching staff's success in the way that other positions don't.
Morel. He doesn't look like an MLB 3B, and while I'm not concerned about his current batting line, the team is likely to look to upgrade the offense, and if they're adding players who push other good hitters to DH, I'd be concerned about the whole being less than the sum of the parts in terms of how that lineup can be deployed. (or maybe injuries make us appreciate that depth if we get it?)
The in-house pen options. Alzolay's arm exploding, along with none of Palencia, Little, Cuas, and Thompson taking a step forward, really puts pressure on the more proven arms. If Wicks comes back strong maybe Brown helps with that, and supplementing at the trade deadline is among the easier changes you can make, but now is the time for someone already in the org to stake their claim by throwing enough strikes(looking at you: Palencia/Little/Hodge) so we aren't trying to juggle 3 relievers in the circle of trust all year.