Idk about 20 years ones (gaming was less available for average person and all we had back then was doom 3, hl 2, unreal tournament 2004 and cs source) but there are cs:go, dota 2, league of legends - they all are more than 10 years old, have sbmm and huge playerbase (war thunder isnt even close to first 2).
Im wondering what toxicity has to do with sbmm, toxicity is a problem for vast array of games with online interactions, including war thunder. Even games that dont have any competitive part like dont starve together still suffer from toxicity.