Manually add a Trend Line using Categorical X-Axis

Hi Team,

I need help with adding a correct formula for a manual trend line because we need to use Categorical as the X-Axis since the Analytics only accepts Continuous to add a Trend Line.

So I used the logic located here - https://techcommunity.microsoft.com/t5/healthcare-and-life-sciences/use-custom-dax-to-create-a-linear-regression-trendline-with-a/ba-p/2405245

It works for the most part but I'm seeing inaccuracies to the line when selecting a country. See examples below:

NOTE: The 2 graphs up top is the manual trend line and the 2 graphs in the bottom is the power BI generated one.

Can anyone help out and suggest a modification of the code.

I'm using the code below:

TLMCall RunCount(X) =
VAR MinDate = CALCULATE(MIN('Return to Office'[ReportMonth]),ALLSELECTED('Return to Office'[ReportMonth]))
RETURN
SWITCH(TRUE(),
ISFILTERED('Return to Office'[ReportMonth]),CALCULATE(DISTINCTCOUNT('Return to Office'[ReportMonth]),FILTER(ALL('Return to Office'[ReportMonth]),'Return to Office'[ReportMonth] <= MAX('Return to Office'[ReportMonth]) && 'Return to Office'[ReportMonth] >= MinDate)),
BLANK()
)

==================================================================================

TLMCall i380 Avg = AVERAGE('Return to Office'[InternalCall])

==================================================================================

TLMCall i380 Avg Prev =
VAR WeekIndexPrev = MAX('Return to Office'[ReportMonth]) - 1
RETURN
SWITCH(TRUE(),
[TL RunCount(X)] < 1,BLANK(),
ISFILTERED('Return to Office'[ReportMonth]),CALCULATE([TL i380 Avg],PREVIOUSMONTH('Return to Office'[ReportMonth])),
BLANK())

==================================================================================

TLMCall Rise =
SWITCH(TRUE(),
[TL RunCount(X)] <= 1, BLANK(),
[TL i380 Avg] - [TL i380 Avg Prev])

==================================================================================

TLMCall Avg Rise (M) =
SWITCH(TRUE(),
[TL RunCount(X)] <1, BLANK(),
ISFILTERED('Return to Office'[ReportMonth]),CALCULATE(AVERAGEX(SUMMARIZE('Return to Office','Return to Office'[ReportMonth]),[TL Rise]),ALLSELECTED('Return to Office'[ReportMonth])),
BLANK()
)

==================================================================================

TLMCall Y Intercept (B) =
SWITCH(TRUE(),
[TL RunCount(X)] < 1, BLANK(),
ISFILTERED('Return to Office'[ReportMonth]), CALCULATE(AVERAGEX(SUMMARIZE('Return to Office','Return to Office'[ReportMonth]),([TL i380 Avg] - ([TL Avg Rise (M)] * [TL RunCount(X)]))),ALLSELECTED('Return to Office'[ReportMonth])),
BLANK()
)

==================================================================================

TLMCall Regression (Y) = ([TL Avg Rise (M)] * [TL RunCount(X)]) + [TL Y Intercept (B)]