outside
1 level of fighter on full casters for heavy armor/con saves,
one level of ranger on fighter to use HM on extra attack+action surge
I do not see any other point in multiclassing as is, it's just delaying your primary class high level features.
also, to me multiclassing is in essence even-split character between two classes and that kind of character is completely underpowered at mid levels and higher.
that is why I am using modified multiclass(dual class to be precise) table of progression.
both classes are always within one level from another and at levels 5,8,11,14,17 and 20, extra class level is given but without HP or proficiency progression:
I.E: 5th level dual-class has class features of 3rd level + 3rd level classes but only 5th level HPs(3+2) and 5th level proficiency bonus.
at the end, 20th level character is 13/13 split with 10+10 levels of HPs and 20th level proficiency bonus.