If you want the weapon to scale with the character so that they keep it for longer, I would design the weapon to enhance the skills the character unlocks as they level up.

At 6th level Rangers can choose another Favored Enemy, so having the weapon do even more damage (+ half your character level piercing damage) against their favored enemy is a nice way to enhance that.

Increasing the critical damage range of a weapon (18-20) instead of the usual 'just on natural 20's' is a nice way to make a weapon more popular with players. even if other weapons they find might do a few extra damage points more consistently, having a higher chance at 'burst' damage is fun and a bit more dramatic from an RP perspective.

One key area that limits the damage of bows and crossbows is loading. Artificers can craft a Repeating Shot weapon that essentially self-loads with magically created ammunition. This is a neat trait that can make a weapon more appealing than others as you no longer have to constantly load (which reduces overall damage output) and you no longer have to worry about running out of ammo if it is difficult to restock.

If you want the weapon to scale with the character so that they keep it for longer, I would design the weapon to enhance the skills the character unlocks as they level up.

At 6th level Rangers can choose another Favored Enemy, so having the weapon do even more damage (+ half your character level piercing damage) against their favored enemy is a nice way to enhance that.

Increasing the critical damage range of a weapon (18-20) instead of the usual 'just on natural 20's' is a nice way to make a weapon more popular with players. even if other weapons they find might do a few extra damage points more consistently, having a higher chance at 'burst' damage is fun and a bit more dramatic from an RP perspective.

One key area that limits the damage of bows and crossbows is loading. Artificers can craft a Repeating Shot weapon that essentially self-loads with magically created ammunition. This is a neat trait that can make a weapon more appealing than others as you no longer have to constantly load (which reduces overall damage output) and you no longer have to worry about running out of ammo if it is difficult to restock.

"I intended [the crossbow] to ... last them for a long time"
This is a matter of scaling with the player, and that is commonly done in a few different ways:
1 - Linking it directly to the class or character level. For example, cantrips typically do an extra die of damage at the 5th, 11th, 17th character levels IIRC. Of course, it doesn't have to be extra damage, it could also provide increasingly significant effects at various levels or compounding effects such as Poisoned, Stunned, Blinded, Incapacitated, etc.
2 - Linking it to the abilities that a class unlocks at different levels. This can make an item specifically tailored to a class or build, and can feel a bit 'shoehorned' in. They are essentially no different from custom-built items.

"I am looking for some balancing feedback"
Regarding the process of balancing, in general, I would advise looking at existing magic weapons that would be appropriate at various levels for a player and seeing what they have in common. This can help you decide what qualities are universally beneficial to the player's character regardless of level, what qualities are going to have diminishing returns as the player levels, and what qualities are going to be desirable.

Regarding feedback for the original crossbow design, in general, it has too many damage types, confusing/unclear wording, and feels unfocused in design. This has been discussed already in previous responses, but typically a magic weapon does one thing very well rather than many different things.