If your bad at texturing a really effective technique is to photobash then touch up the texture with added shadows and highlights. The pic rel is a 512x512 texture done by using Blenders stencil feature and was edited with Clip Studio Paint. Since your a solo dev this technique would probably be the best as it's quite quick while still being able to produce that early to mid 2000s style. I go for a more 2000-2005 style but you could definitely make some stuff more akin to model posted in the OP with some trial and error, although you would definitely need some more texture painting. As you said its really difficult to find resources on this era of graphics but I've done some digging and here is some stuff I've found.

This channel is from a guy who is versed in the style and has a lot of good resources on his website too. Specifically has a really good character tutorial that's even using the software that was used during the era, 3D Studio Max and Bodypaint
https://www.youtube.com/@videogamemaker

I've also found some books on the subject, particularly one from 2006 called "3D Game Textures: Create Professional Game Art Using Photoshop". It might be hard to find torrents of books like these due to the age and lack of interest but they're a resource straight from that era. I haven't started reading them yet because I'm working on a project atm so I can't say how effective they are but there is certainly some techniques to be gleaned.

Also study the models and environments from games of that time, I take a ton of screenshots from games like Oblivion, Postal, RTCW, and the like. I'm glad that other people are passionate about this style, so many games are based off of PS1 but this "mid poly" era gets skipped over entirely it seems.