Democrats have an easier time regaining control of the US Senate in 2022 than 2020.

In 2020, the Democratic held US Senate seat likely to go Republican is AL(Jones-D).-1D.
Democrats will hold onto DE(Coons-D),IL(Durbin-D),MA(Markey-D/Kennedy-D),MI(Peters-D),MN(Smith-D),NH(Shaheen-D),NJ(Booker-D),NM(OPEN Udall-D/Lujan-D),OR(Merkley-D),RI(Reed-D),and VA(Warner-D).
Democrats will pick up AZ(McSally-R/Kelly-D),CO(Gardner-R/Hickenlooper-D), and NC(Tillis-R/Cunningham-D) +2D
If Warren(D-MA) is elected POTUS-, the MA US Senate seat goes Republican until the winner of the 2021 special election is decided. Top tier MA Republicans are Baker,Weld,Polito,Healey,and Swift. +1D
To regain control of the US Senate, Democrats need to win either or both of the GA US Senate seats,ME and the MA special Election.
In 2022, the most vulnerable Democratic held US Senate seats are AZ(Kelly-D) and GA(Lieberman-D). Democrats are likely to hold onto AZ and GA.
The most vulnerable Republican held US Senate seats up in 2022 likely to go Democratic.
FL(Rubio-R) Gwen Graham-D.
IA(OPEN Grassley-R) Finkenaur-D or Axne-D.
NC(OPEN Burr-R) Erica Smith-D.
OH(Portman-R) Tim Ryan-D
PA(Toomey-R) Brendan Boyle-D
WI(Johnson-R) Ron Kind-D