Need help building a Formula–Text field

I’m working in Quickbase and need help building a Formula–Text field based on selections in a Multi-Select Text field.

Requirement

The formula should return one of three designations based on a strict priority:

1. Tier 1 — highest priority
2. Tier 2 — medium priority
3. Tier 3 — lowest priority

When selections from multiple tiers are present, the formula must return the highest-priority tier.

Current setup:
The source field is a Multi-Select Text field(20 options). I created a helper Formula–Text field using:

Lower(ToText([Multi-Select Field]))

The helper field correctly displays the selected options as semicolon-separated text.

However, formulas using the following methods do not consistently recognize all selected values:

Contains, Find,  Trim,  RegexMatch

Even a basic test such as this returns the false result, although the helper field visibly contains the phrase:

var text Criteria = Lower(ToText([Multi-Select Field])); If( Contains($Criteria, "example selection"), "MATCHED", "NOT MATCHED" )

I also tried:

• Adding semicolon boundaries
• Accounting for spaces around semicolons
• Matching first, middle, and last list values
• Removing punctuation from the configured option
• Recreating the option manually
• Using Find() instead of Contains()
• Comparing the converted value directly
• Using a formula query with the Multi-Select field ID and a HAS operator

The formula-query attempt returned blank.

Constraints

• I need a formula-field-only solution
• I do not want to use Quickbase Pipelines
• I do not want to replace the Multi-Select field with many individual checkbox fields
• Exact selection matching is preferred to avoid accidental partial matches
• The solution must work when one or multiple choices are selected
• The priority order must be preserved

What is the correct supported Quickbase formula syntax for determining whether a specific option is selected in a Multi-Select Text field? Is there a native list-membership function or formula-query method that works reliably for the current record?