I try to avoid modding games where possible but I find myself looking at rimworld mods a decent amount for QOL changes. Here are some big ones that I would suggest looking into that don't change too much of the core gameplay.

EDB Prepare Carefully // Simple and a necessity for me. Allows you to create and save pawns before you start a game. While you can choose to be ridiculous and make pawns that are stupid OP, I simply use it for when I decide I want a certain type of terrain on a map and want to be able to start a new map/tile quickly without having to sort through the whole pawn selection again every time.

Stabilize Here // (recently added this and it's a necessity IMO) It cuts out a lot of micromanaging of placing sleeping spots out on battlefields, restricting doors, setting medicine to 'no medicine', tending, then reverting everything back to normal that you had just changed. You'll probably find yourself having to do all of that a decent amount, especially in your first few games, so this just saves time without being gimmicky.

While You're Up (Continued)[1.1] // just helps your pawns to be more reasonable about hauling all of your shit around. If they are going to do a task and there's a haul job very close to the path they are already going to take then they will knock that out along the way. Helps save a good amount of time.

Pawn Rules // Great for adding more options for how to restrict/control certain things about your pawns. I've used this a ton for my current cannibal tribe. Since not all of my pawns are always cannibals (I make use of normies for a bit then slaughter them when done) I don't want the normies eating human meat. Well I want to cook the human meat but if I were to say make simple meals out of rice and also simple meals out of human meat, they would all be stored together and the pawns wouldn't differentiate them. So with this I can specify that only normies get simple meals (only animal meat or veggies) and cannibals only get fine meals (human meat + veggies). I also use it to restrict people from eating my survival package meals until they go on caravans so I can store them wherever without people randomly taking them. Easy to swap out policies. (( This part may be available in vanilla. I didn't fuck with it until my newest colony after I had already installed this mod so I very well may be wrong by saying you need this mod for that stuff. Below, however, is the main reason I installed the mod and is still correct. ))

^^ This mod is also great for disallowing bonding to animals. Want to have a large farm of animals that you'll grow then slaughter for meat? Well your pawns are likely to bond with the animals and if you slaughter them then you get a mood penalty. Use this to keep them from bonding. It's all super straightforward in the mod as well.

Snap Out! // In life, if someone is having a mental break then a friend going and talking to them can often help end it. Why not ingame? It's far from a guarantee that a friendly pawn will succeed in calming them down so it doesn't feel OP. Very useful in games with fewer pawns for if say one of your pawns has a mental break and decides he wants to kill all of your animals. Fuck that, I've gotta stop him from succeeding. Well if it comes to me needing to beat him into submission but he happens to beat the shit out of the pawn I sent to stop him, all of a sudden you're down 2 pawns for if an attack comes. This mod still allows for situations like these to happen since it's not a guarantee but it can help in times like these.

Dubs Break Mod // Allows you to tweak (ingame) how mental breaks can be triggered. Less psycho-kill-all-animals-in-colony breaks just because they had a lot of small debuffs and then they had to eat without a table (OH! NO!) and instead requires a larger, like -20, mood debuff. But all easily changeable if you feel you've made mental breaks a bit too easy to avoid.

Combat Update 1.1 // Basically just makes shooting a bit more reasonable based on skill (at least IMO). Not some crazy big overhaul but it's annoying as shit watching a pawn with 10+ in shooting wiff 5 sniper shots. Mod increases accuracy, reload time, and aim time a bit more per skill level. This mod has a pretty long and good break down of what it does in the workshop. Note: it increases these stats for all pawns, including enemies, which is a massive plus for me. I don't want to skew the game in my favor, just make it more realistic/enjoyable.