Lookup with mutiple table - If else loop condition

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Source: PO Table and Org Tables:

Relationships:

Measure:

Requester Level = 
var _sel = SELECTEDVALUE('PO Table'[Requester])

var _LevelID = SWITCH( TRUE(), 
    -- is Engineer?
    LOOKUPVALUE('Org Table'[L4 ID], 'Org Table'[Engineer], _sel) <> BLANK(), LOOKUPVALUE('Org Table'[L4 ID], 'Org Table'[Engineer], _sel),
    -- is team leader
    LOOKUPVALUE('Org Table'[L3 ID], 'Org Table'[Team Leader], _sel) <> BLANK(), LOOKUPVALUE('Org Table'[L3 ID], 'Org Table'[Team Leader], _sel),
    -- is Manager
    LOOKUPVALUE('Org Table'[L2 ID], 'Org Table'[Manager], _sel) <> BLANK(), LOOKUPVALUE('Org Table'[L2 ID], 'Org Table'[Manager], _sel),
    -- is Senion Manager
    LOOKUPVALUE('Org Table'[L1 ID], 'Org Table'[Senior Manager], _sel) <> BLANK(), LOOKUPVALUE('Org Table'[L1 ID], 'Org Table'[Senior Manager], _sel),
    BLANK()
)

RETURN _LevelID

Final output: