For a challenge

[8wGremlin]

For a challenge, I've been given stats, race, and class.

Stout Halfling, Sun Soul Monk, starts at level 3 have Dex: 18, Con: 14, Wis: 16

Limitations: divine magic is severely limited, we are playing in a spell jammer like Universe.

So build - thoughts - feats - things to aim for, etc etc.

If you could point me in any way to make improvements I'd me happy.

[TenaciousJ]

Sun Soul is in a weird spot because a lot of the time, you'll feel like a monk with no archetype.  It gives extra options rather than enhancing the features of the base monk.  The versatility is nice sometimes.  Monk doesn't play well with multiclassing because the features past level 1 are not very useful without ki to fuel them.

Monks are mostly functional without feats but demand lots of ASIs.  You'll likely just want to increase your Dex to 20 and then Wis to 20.  Just the ASIs will fill up the build to level 12, leaving you two feats at 16 and 19 if you actually make it that far.

Mobile allows you to more effectively move in and out of melee range of multiple creatures while using Stunning Strike to set up your allies for advantage.  It's most useful when spacing does not allow you to find a path that avoids opportunity attacks.  It's less useful on Sun Soul than most other ways because Sun Soul has no reason to go into melee range if you're not trying to stun.

Spell Sniper can be useful to Sun Soul.  Though it does not increase your range since the level 3 feature is not a spell, the level 3 feature does use ranged spell attack rolls, and so it benefits from Spell Sniper's effect to ignore half and 3/4 cover.  You likely won't have the ability scores to make any long range cantrip work since all the 120 ft. cantrips are Int or Cha based, but Booming Blade has some niche use and fits the parameters for Spell Sniper's cantrip.  The feat is something you'd only consider however if you somehow find yourself with maxed out Dex and Wis with Mobile.

[awaken_D_M_golem]

any Magic Item crafting available?

None of the surviving Monk Handbooks are fully updated.
Hex's necrotic + Sun Soul's radiance, is fluff wise shaky.

If you could pull it together (y'know for the DM and might need cookies) , the 2nd newest Ranger update since that's supposed to be a chassis, combined with the older Spell-Less Ranger, could be a decent 2 or 3 level dip.

Eberron Dragonmarks are in the very first UA.  Mark Of Hospitality feat is Halfling specific, and has some interesting utility.  Saves a few picks from the other caster PCs.

Light Crossbow is quite enough ranged oomph for levels 3 and 4.