Make two disconnected slicers filter a matrix

I’m trying to make an Availability matrix respond to two slicers that come from the same “Skills” fact table but different attributes (and keep relationships single‑direction).

Visual setup

• Matrix rows: FullName_All[FirstName] (dimension)
• Matrix values: Hours (skills aware) measure
• Slicers:
  • Certifications[Certification] (disconnected list from Skills where Attribute = "Certifications")
  • Screening[Screening] (disconnected list from Skills where Attribute = "Screening")

Model (relevant parts)

• FullName_All is the conformed people dimension.
• Single‑direction relationships from FullName_All → Availability sheet, Advanced, Skills, WIP Report, Query.

Calculated tables for slicers:

Certifications :=
DISTINCT(
    SELECTCOLUMNS(
        FILTER(Skills, TRIM(Skills[Attribute]) = "Certifications"),
        "Certification", Skills[Value]
    )
)

Screening :=
DISTINCT(
    SELECTCOLUMNS(
        FILTER(Skills, TRIM(Skills[Attribute]) = "Screening"),
        "Screening", Skills[Value]
    )
)

Working measures (each works on its own)

• Certifications only:

Hours (skills aware) =
VAR HasCertFilter = ISFILTERED(Certifications[Certification])
RETURN IF(
    HasCertFilter,
    CALCULATE(
        SUM('Availability sheet'[Hours]),
        CROSSFILTER(FullName_All[FullNameKey], Advanced[Full Name], BOTH),
        CROSSFILTER(FullName_All[FullNameKey], Skills[Full Name], BOTH),
        KEEPFILTERS(FILTER(Skills, TRIM(Skills[Attribute]) = "Certifications")),
        TREATAS(VALUES(Certifications[Certification]), Skills[Value])
    ),
    CALCULATE(
        SUM('Availability sheet'[Hours]),
        CROSSFILTER(FullName_All[FullNameKey], Advanced[Full Name], BOTH),
        CROSSFILTER(FullName_All[FullNameKey], Skills[Full Name], BOTH)
    )
)

• Screening only (same pattern, works):

Hours (skills aware — screening only) =
VAR HasScreening = ISFILTERED(Screening[Screening])
RETURN IF(
    HasScreening,
    CALCULATE(
        SUM('Availability sheet'[Hours]),
        CROSSFILTER(FullName_All[FullNameKey], Advanced[Full Name], BOTH),
        CROSSFILTER(FullName_All[FullNameKey], Skills[Full Name], BOTH),
        KEEPFILTERS(FILTER(Skills, TRIM(Skills[Attribute]) = "Screening")),
        TREATAS(VALUES(Screening[Screening]), Skills[Value])
    ),
    CALCULATE(
        SUM('Availability sheet'[Hours]),
        CROSSFILTER(FullName_All[FullNameKey], Advanced[Full Name], BOTH),
        CROSSFILTER(FullName_All[FullNameKey], Skills[Full Name], BOTH)
    )
)

However, I can't seem to figure out how I can combine these into a single measure.

Constraint to keep

• Expertise slicer is built from Advanced (SkillCategory_Slicer and SkillLevel_Slicer).
• The hours measure must continue to respect Expertise via:

CROSSFILTER(FullName_All[FullNameKey], Advanced[Full Name], BOTH)

• The matrix has a visual‑level filter which uses FullName_All to hide names when only Skill Category is selected without Skill Level.

Question

• What is the correct, minimal DAX pattern to combine both disconnected slicers (Certifications + Screening) so the matrix shows:
  • certifications only,
  • screening only,
  • the intersection when both are selected, while still respecting the Expertise slicer?

Thank you.