I assume you hold to the idea that "Scripture interprets Scripture" - let's look at the parallel passage in Titus.
Look at what it's saying...he goes into a town and finds an upright man - above reproach, married to only one wife, etc. What are the requirements, though? Again, Paul reiterates, he MUST be above reproach. Next, he MUST be the husband of one wife, right? Wait, no, Paul skips right over that! He goes straight to the other requirements - not arrogant, not a drunkard, upright, etc.
That is the requirement. That Timothy should place someone in eldership
IF a man is blameless, the husband of one wife, having faithful children not accused of dissipation or insubordination....
You are assuming that the "if" is conditional to blameless, the husband of one wife...... it is not, that "if" is conditional to Timothy finds such a man.
It reads like this.....
"For this reason I left you in Crete, that you should set in order the things that are lacking, and
appoint elders in every city as I commanded you IF a man is blameless, the husband of one wife, having faithful children not accused of dissipation or insubordination.....
Those are the requirements along with everything else he said in 7-9.
Those requirements doesn't change from 1 Timothy 3. Paul gives the qualifications to Timothy in 1 Timothy 3 as a list of qualifications for elders....YES "MUST BE" is there with a list of qualifications. In the book of Titus 1, Paul is telling Timothy to place elders there if he can find such a man. Those qualifications are supposed to be the opposite of what he has been finding in Crete in verse 10-16 in Titus.
Read those requirements again, it starts in verse 6, you can't skip those verses because it does not say "husband of one wife" when it says that in verse 5 and is echoed in 1 Timothy 3:2 when it says (A bishop then must be blameless, the husband of one wife, temperate, sober-minded......etc)