There are several reasons that this probably won't be the case.
1) There were rumors that STID did not satisfy the studio's desire for Marvel-like box office. The budget would be reduced it was said. It was..from $190 to $185 million,
Reports up until quite close to release had it at $150 million. It is possible the budget blew out, particularly as work was started then abandoned on an earlier script.
Also, while ID made less than its predecessor in the US, it made more worldwide. Beyond made less than either film in both respects.
2) Foreign investment. More likely than a reduced budget, will be a shared production budget, as with Beyond. In fact, Alibaba even paid for marketing and distribution in China.
Sure, but it's not a donation. They take a cut of the box office in return. It reduces the risk somewhat, but it also reduces the reward, and makes other markets more important. Beyond was down in almost all of those.
3) The 3 films have made over $1.2 billion in BO alone. Over $1.5 billion with disc sales. This does not count all secondary revenue, but Paramount is literally swimming in Trek money. Beyond was their top moneymaker, a tentpole and continues a niche, but popular franchise.
Beyond was their highest grossing film of 2016, but there's no way it was their most profitable.
Beyond made $158 million in the US and $343 million worldwide on a $185 million budget. As one example, Arrival made $100 million in the US and $198 million worldwide on a $47 million budget.
I know which I'd be happier with if I was at Paramount.
Disc sales may narrow the gap, since Trek fans love to complete their collection (though I haven't bought it yet in protest at the splitting of features), but that's a big gap to fill.
In short, they'd be extraordinarily bold to not reduce the budget on a series which already has a limited market and is showing diminishing returns - if they make another one at all.