Thanks for the feedback, I'll consider how to address this!

Get a Bladesman, make your other Fighters learn Legion, use Legion to give them the Bladesman's Phase Strike and give your Fighters melee weapons. You end up with a blink-equivalent ability which'll have a higher range and be instantaneous at a higher level.

Thats great to know, but its such a terribly niche way to do it. Since RNG is RNG, getting a bladesman can be impossible sometimes. In my current run I have made 10 martial books, 6 of them came out as death knight, 2 shadow, and 2 monk.

I have requested a caravan from the arcane fold 2 times and each time they didn't have and fighter books at all, just mage books. If I happen to find a bladesman class in the future I will try using legion to get phase strikes on my fighters like you said though, thank you.

Totally forgot Training. Once your Fighters reach level 20 they unlock their Training skill, which they can use to give other Fighters a bit of XP. If you enable autocast they should use it at least sometimes. They also sometimes just teach eachother even without that Skill as just a social interaction.
I think i usually end up using an Orb of Souls to yoink a bladesman trader's soul to then infuse into a colonist of mine.
Once you get Phase Strike your fighters usually end up leveling incredibly quickly because they can use it once every few seconds; your hauler/fighter, if you have one, will suddenly turn into one of if not the strongest colonist you have.

Fighting fires has given me lots of xp for melee skills