The Chargers should make finding a true CB1 their main offseason priority.
Michael Davis has made long strides in his development since joining the Chargers in 2017 as an undrafted free agent. He has developed into a fine cornerback. That said, the Michel Davis CB1 experiment was a failure. Davis' length and speed allow him to match up with all kinds of receivers, from Tyreek Hill to Darren Waller. But when tasked with eliminating the opposing team's top option, he became a liability.
As well coached as the 2020 Rams defense was, having Jalen Ramsey made things much easier for Staley. Having the luxury of taking care of the opposing team's No. 1 option in the passing game, while creating 2-on-1s on the rest of the offense was a main factor in his defense being so good on 3rd downs, as mentioned in this 2021 article from Steven Ruiz.
Staley's defense invites a team to run the ball, and makes sure to take care of the passing game first, and allocate whatever resources are left to defend the run. It's a very modern defense in this regard, as analytics will tell you passing is the way to win games in today's NFL. It makes sense that a defense's main priority should shift from stopping the run, which most current defenses fret over, to stopping the pass.
It didn't work in 2020, but with the right talent and personnel along the defensive line, Staley's defense will quickly thrive. And fixing the run defense is obviously a priority. The defensive line needs to be revamped, but that's not the thing that will take the Chargers' defense to reach it's full potential.
As stated before, Staley's modern defense focuses on stopping the pass first. That means that the first order of business in designing a game plan for a specific team is taking away it's main option. With the Rams, this simply meant having Ramsey shadow the opposing team's #1 and that's that.
With the Chargers, Staley often tasked Davis to do the same, only to adjust mid-game with safety help when Davis started to struggle. Davis didn't always struggle, but he wasn't anywhere near consistent enough to let Staley run the defense he envisioned.
Asante Samuel Jr. showed flashes in his rookie season, even as he dealt with concussion issues. It's expected for him to take the next step in his development, but the team needs a CB1, and he might never be that guy. Samuel Jr. has limitations, mainly his stature and discipline. Top receivers will know how to exploit that.
Samuel Jr. does have traits that could see him develop in that direction, as he is very sticky in coverage and great at producing incompletions. He thrives by making receivers uncomfortable every step of the way, from the release to the catch point. Even so, Samuel Jr. can be a better asset to the defense by moving around and creating mismatches, using his physicality to disrupt routes and putting his ballhawk insticts in position to create turnovers.