It's not a big surprise the Under is 3-0 in Chargers' games this season. The Chargers under Anthony Lynn are a dead-nuts Under team. Lynn runs a conservative offense relying on a strong defense to win the overall field position battle. Lynn is not going to change that style especially with rookie QB Justin Herbert set to face the toughest defense he's ever seen.
The Buccaneers have an upper level defense. They are fourth in takeaways and fourth in total yards. Tampa Bay led the NFL in run defense last season. This year they rank fourth. 
The Buccaneers' offense, though, remains a work-in-progress. Tom Brady is far less of a risk taker than Jameis Winston preferring short, safe throws instead of attacking over the top. Brady is still trying to get in sync with his new team. Brady is getting a downgrade in offensive lines from the ones he's had in New England.