I remember seeing a guide on this before, but... I can't find it now. I'm way more familiar with blender than I am with milkshape... Milkshape's ui also looks very intimidating and unfamiliar to me... I recently did some Sonic Adventure 2 mods, which required messing with models, so I kinda get what I'm doing in blender, especially compared to milkshape, where I just... look at it and freeze up.
Additionally, is there anything special I should know? any dos and don'ts?

Yes, you can. There are fewer tutorials for it (especially for body/CAS meshing and items with animated parts), but there are plugins.

I think the newest plugins for GMDC files are these:
https://modthesims.info/d/656032/th...ender-2-80.html

If you're doing from-scratch models, I suggest looking into general low-poly meshing tutorials with Blender (low-poly, because it's always a good idea to start low and add on where it's actually needed, than start very high and have so much you need to reduce), plus UVmapping. Saves you from getting stuck in a meshing project because a TS2 tutorial doesn't explain well enough, and also lets you use info from for instance Milkshape-based tutorials without getting too hung up in how to mesh/UVmap/etc.

A lot of the older tutorials give you good pointers on TS2-spesific things, so it's a good idea to read through them even if they aren't Blender-spesific. If you can do stuff in one meshing program with the help of plugins, all you really need is to read up on how to use the plugins, and how to transfer the files to and from SimPE so everything works.

(Personally I haven't looked into the plugins, and mostly use Blender for some meshing and fixing stuff Milkshape isn't too helpful with like UVs and such, or converting 4t2 - but anything having to do with joint assignments I still do in Milkshape, mostly because I'm used to how it works. Blender has a steep learning curveand I just haven't had the energy to learn yet another program, especially with the wildly different UI from the programs I learned meshing with. I have used several different meshing program over the years for TS2 projects, mostly alongside Milkshape. Did the meshing in other programs, and the final touches (joint assignments, small edits, size) in Milkshape. Worked quite fine that way. For non-jointed meshes you can import directly (as OBJ) from Blender to SimPE, with the correct settings).

Thank you so much! I'm mostly gonna be editing existing meshes but I do wanna do some sims 3 & 4 conversions to 2 once I get more familiar.