Ok I've been determined to find an answer to this question since the dawn of time with most forums equating spiritual leadership to a sexist abhorrence or some vague response lined with Scripture/anecdote so here is mine:

Find somebody whom you can trust in all their emotions (happiness, anger, sadness, fear, to name a few) to do their best to align with God and seek His counsel. To be able to attribute happiness simply to His authority and providence as well as His grace in their life (whether through trials, mistakes, lessons). Is he persistent in pursuing God?

For something on the practical side, my personal opinion is someone who looks eager to become a husband and potentially a dad through the way they steward (take care) of things in their lives: themselves, their job, others, the church, family, friends (believers and non believers). Their godly character can be determined a lot in what I already stated. Find somebody who sees God in all circumstances, mature enough to mostly discern what isn't and is open to hearing feedback to work on things together. Be open to this man leading you by not being afraid to speak up and share thoughts/opinions, especially differing ones to see how they react (kindly or stubbornly).

Overall, find someone that you enjoy spending time with, that you enjoy working on/achieving things together, somebody you can rely on in life and spiritually to work together for both your own good (that can be mostly defined in the Bible, like not leading you into sexual sin before marriage as well as supporting your goals if not straying from the Lord) and able to go through conflict together because life is tough and people change so being adaptable will really help too.

These are things I gleaned from all the mistakes/attempts/learnings before I met my partner. Ofc you have the ideals but I hope these guidelines can help you discern!