Oracle is not even in contention. Not only do they lack the expertise, they have a terrible reputation and offer nothing unique. Alibaba is a different story. China is a huge market that western companies typically stuggle in, and many of the large businesses there do not have the infrastructure debt of older US companies. Alibaba has massive infrastructure, strong technical expertise and their cloud offering has been expanding rapidly, I would definitely watch out for them.
Alibaba can definitely take a huge chunk of the Chinese market - but internationally? They're Chinese. General opinion in Western politics is to distrust Chinese-controlled stuff, as evidenced by the handling of the Huawei case.
Alibaba is well positioned to capture a large share of the small but growing African market.
Fun fact: Aliyun (Alibaba cloud) has more revenue than GCP
So I just took a look at their offering and was shocked to see just how many services they offer. Way more than I had anticipated for a provider I don't really hear too much about.
Love the Aliyun portal UI. By far the simplest and most accessible cloud portal UI when compared to AWS, Azure or GCP.
Digital Ocean UI also awesome if you consider them a player in the field.