Add values from two tables that share a date

There are various approaches. Regardless of which approach, you should get a calendar table. 
https://exceleratorbi.com.au/power-bi-calendar-tables/

then you can either join the calendar table to bith of the tables to have (one to many), use the calendar table in your visual and then write a measure = sum(table1[amount]) + sum(table2[offset])

or, if it were me, and if the tables actually look like those you posted (ie, there's nothing your holding back and not telling me), I would do the following 

in power query, create transform table 1 to be like

date, attribute, amount

1/1/24, "Amount", 450

etc

table 2, exactly the same headers but put "offset" as the attribute 

append the 2 tables together and load a single table

still join to the calendar table as above.

you can simply drag the amount column into the values section and even use the attribute column in your visual. 

Hello kman42 

You can acheive this doing by following steps:

1. Create a Date Table by going to modelling and in the new table add the following dax:

Date =

ADDCOLUMNS (

CALENDAR( "1/1/2024", "12/31/2024"),

"ShortDate", FORMAT([Date], "DD-MMM"),

"Date_Date", FORMAT([Date], "MM/DD/YY"),

"DateAsInteger", FORMAT ( [Date], "YYYYMMDD" ),

"Year", YEAR ( [Date] ),

"Monthnumber", FORMAT ( [Date], "MM" ),

"YearMonthnumber", FORMAT ( [Date], "YYYYMM" ),

"YearMonthShort", FORMAT ( [Date], "YYYY/mmm" ),

"MonthNameShort", FORMAT ( [Date], "mmm" ),

"MonthNameLong", FORMAT ( [Date], "mmmm" ),

"DayOfWeekNumber", WEEKDAY ( [Date] ),

"DayOfWeek", FORMAT ( [Date], "dddd" ),

"DayOfWeekShort", FORMAT ( [Date], "ddd" ),

"Quarter", "Q" & FORMAT ( [Date], "Q" ),

"YearQuarter", FORMAT ( [Date], "YYYY" ) & "/Q" & FORMAT ( [Date], "Q" )

)

2. Create a relantionship between Date and other tables:

3. Create a measure:

Amount + Offset =

Var A = SUM('Table 1'[Amount])

VAR B = SUM('Table 2'[Offset])

RETURN

A + B

4. Result:

Let me know if you got this. Kudos!

hi kman42 ,

To start less stressfully, you can add a calculated column in table1 like this:

Column =

[Amount] +

LOOKUPVALUE(

    table2[offset],

    table2[date],

    table1[date]

)