mop, you assume a 'hypothetical' situation, overlooking step one. How do you know airspeed is unreliable.
If only one EFIS airspeed display is suspect then perhaps a comparator alert is given.
If a background system is the problem, such as airdata, again there could be an alert or failure warning.
A more complex problem could involve several air data systems like AF, which challenged the automatic 'two out of three' comparator logic, and then handed the situation to the pilots to solve, - where the complexity of situation could 'fool' the two out of three pilots cross check ( but there were only two).
The first step is to determine what the problem is; a single or multiple airspeed display, or airdata which could involve many other aircraft systems - flight control, altitude, vs, ...
I suspect the checklist or memory items (I'm not T7 qualified) relates to specific circumstances. These conditions must be identified before acting. Check any explanation given by the manufacturer, is the malfunction alerted, if so how, what is the drill title, and what alternative actions are there.
Your scenario assumes a situation, then jumps to an activity which might be inappropriate for the actual situation.
Step '0', understand the situation, avoid expectation (manage surprise);
then apply the drill according to your current understanding, consider what should or could happen,
then reassess the situation according to your projections and revised actual conditions,
then reassess the situation, ...
then, ...