They threw their development time into their core market (PC) instead.
LoL wouldn't have been allowed to market in China and would have been fighting its own popularity in SEA, Honor of Kings can only gross so much because it is overwhelmingly shilled in China and their entire gaming market is mobile. The point of getting Riot was to allow Tencent to dip into the West and steal expertise, not the other way around.
Their first launch was Valorant, which bumped them up from ~2bn on LoL alone, to 3bn between the two games. Their mobage (ccg and autobattler) have "bad" monetization, but a very high pickup rate for the US mobile market, increasing reach for future titles or updates that add more whaling.
Next up is their fighting game, which is entering a market that is so desperate for anything that isn't shit that people are willing to play GG Strive, then the MMO and the single-player RPG... They can fuck around with mobile after they've finished swallowing the English-speaking (and KR/JP) PC market whole.
In the end, Tencent is most likely directly responsible for Wild Rift getting held up so long, since approving or enabling it too early in China would let the gweilos eat into their pocket market. Now that Wild Rift is finally allowed in China and is too late to ever catch up, they can just add "more popular than LoL!" to their advertising, same as how they've handled all the CSGO ripoffs released there.