Why are Republican Governors so much more popular than Democratic Senators?

[GeneralMacArthur]

According to Morning Consult, popularity (within their own state):

Baker:  73/16
Hogan:  70/14
Scott:  64/23
Gordon:  63/13
Sununu:  62/24
Abbot:  59/24
Hutchinson:  59/24
Little:  59/22
Stitt:  59/19
Burgum:  59/19
DeSantis:  58/22
Ivey:  57/30
Lee:  56/19
Bryant:  55/26
Carney:  55/25
Herbert:  55/28
McMaster:  54/26
Ricketts:  54/34
Bullock:  53/31
Kemp:  53/28
Wolf:  53/33
Bel Edwards:  52/31
Ducey:  52/30
Kelly:  52/23
Sisolak:  52/25
Holcomb:  51/23
Walz:  51/29
Evers:  49/34
Cooper:  48/30
Cuomo:  48/41
DeWine:  48/32
Noem:  48/41
Parson:  48/25
Inslee:  47/35
Grisham:  47/37
Mills:  46/44
Polis:  46/35
Whitmer:  46/34
Murphy:  45/38
Reynolds:  45/41
Dunleavy:  43/41
Newsom:  43/36
Pritzker:  43/42
Justice:  42/47
Northam:  42/38
Brown:  38/50
Ige:  36/50
Raimondo:  36/56
Lamont:  35/48
Bevin:  34/53

The top 14 most popular governors are Republicans, constituting 76% of the top half.
In contrast, Democrats are 72% of the bottom half, including 13 of the 17 most unpopular governors.

Why do Republicans stomp Democrats on this metric?