i think rome total war was the gold standard in the 00s and even a good bit into the 10s. occasionally infuriating with how units just will not do what you say sometimes, but it’s for a great balance between turn based campaign map and real time battle map
it’s not the most complex, it’s very simple in everything it does in both campaign and battle map, but there’s enough variety and different things to keep track of that you trick yourself into thinking you’re smart by being good at it. i’d also say barbarian invasion is better than the original game (i’ve also ONLY played as goths and sarmatians)
90s gold standard was probably command and conquer, and probably specifically red alert. it’s also a very simple game and basically an action run and gun game disguised as strategy which is how it got so mainstream but you WILL get raped if you just go gung ho. the dune 2 rts game i think is equally as good and is the same engine
if you wanna go super autistic i’d highly recommend blitzkrieg, theatre of war 2 and stalingrad. the ww1/2 games are always the most “specific”. the autisticity of an rts game directly correlates with the percentage of russians in its fanbase