First, you have to build one, and Miami has not had a good offensive line for a LONG time. Only the short run of the "unicorns" in 2016 (Branden Albert, Laremy Tunsil, Mike Pouncey, Jermon Bushrod, and Ja'wan James) was anything approaching a "good OL, and even that line got Ryan Tannekill's knee injured.
This year, they made several mistakes both on and off the field on the OL (and the entire offense for that matter). First, they dismissed Chan Gailey as the offensive coordinator, and then failing to hire an experienced coordinator, they named two assistants as "Co-Coordinators". Miami then hired an OL assistant from Seattle (a team not known for its stellar OL play) as a first time offensive line coach. They also hired a coach Tua Tagovailoa had in college as his QB coach.
On the field, they traded Erik Flowers to the Washington Football Team in a swap of late round draft picks. Flowers has since graded out as one of the top OL for WFT. During training camp, they released Jermaine Eluemunor during their cut down from 85 players. Eluemunor is now a starting OG for the first place Las Vegas Raiders. In April, they drafted Liam Eichenberg, a LT who they immediately tried to start at RT, then LG, and finally were forced to put him back at his natural LT position because the one they drafted last year with the 18th pick (Austin Jackson) has severely regressed. They moved Jackson to LG two weeks ago, and his performance so far as been spotty at best. They are playing a journeyman at RT (Jesse Davis), who in week 2 completely whiffed the block on a Bills DE that resulted in the hit that fractured Tua's ribs. Across the Miami offensive line, they have a grand total of 9 years' experience. For an in-division comparison, the Bills OL has a combined 29 years of player experience.
The result has been evident each week on the field in the forms of poor game planning and adjustment, poor communication of plays to the QBs, a nearly nonexistent running game (they also passed on drafting Najee Harris this year), the need to employ a short to medium passing game because QBs have less than 2 seconds to get rid of the ball, and unimaginative offensive schemes. Its also resulted in mistakes that have had game altering consequences, like this play from week 3.
Its no surprise the Dolphins are currently 1-6 (will likely be 1-7 after Sunday's Inquisition in Buffalo), and I frankly don't see them winning more than 3-4 games the rest of the way no matter who is under center for them. I also see these decisions likely resulting in an early Black Monday firing of Brian Flores, who at the end of last season was a top candidate for Coach of the Year.
The Bengals last year learned an expensive lesson in Joe Burrow's knee injury of the need to protect your young QB. I'm hoping Tua is able to get a line in front of him, or ends up going somewhere that has a good OL.