I order the positions by impact in the tiers below
QB
WR
CB
All other defensive coverage players--this where I see safety fitting.
Pass Blockers
Pass Rushers
I think Adams is a bit of a special case--because of his specific skill set. He is a box player and I see him taking on the role of the third LB in Seattle's defense. Seattle does not want to play a nickel often because they are so focused on stopping the run. However, Kendricks and KJ get exposed on crossing routes. Adams makes them alot better here and they added Brooks in the draft. I see them both starting with Bobby. He is a great player but not an impact player. He will make plays that impactful but over the course of a game he is not elite in the most important areas--coverage or under 2.5 sec pass rush. I don't see him winning versus elite tight ends in the pass game. Whereas tp me Littleton was elite because of his coverage skills.
Overall, Adams is the exact type of player I would avoid because I dont want to pay market leading money for a lesser impact player. Not comparing them as players at all, but Adams' situation is how I viewed Peters with the Rams. Peters is good but not worth the money. Adams is great but not worth the money because of the impact he has on games. However, Donald isnt worth the money either but is at worst Hall of Fame and likely the best interior DL of all time. So, sometimes its unavoidable. Its very hard to be worth at non QB, WR, CB on these plus 20 mil per deals.