Soya isn't healthy either for your or the planet. Large areas of rainforest and cerrado in South America are razed in order to start soya plantations.
All the wildlife in those areas is biologically cleansed. It requires huge inputs of industrial agricultural technology and chemicals such as glyphosate pesticides, which are causing a massive spike in cancers, horrific teratogenic birth defects, miscarriages and still births in Argentina... also catastrophic to ecological habitats and cruel to all the animals that live there; fertilisers which require massive fossil fuel inputs in order to manufacture them; gargantuan machinery that obliterates mammals and other small creatures in the paths; rivers are diverted and groundwater mined for irrigation - which is curtains for all the creatures dependent on them. Then has to be shipped great distances across oceans on polluting super tankers. Large amounts of energy to render the raw beans into milk. etc etc
It's also terrible for human health at the consumer end of the chain. Soya is a terrible endocrine disruptor, can seriously affect thyroid function and lead to diseases like hashimoto's, low sperm counts in men and diminished fertility. East Asians have traditionally used it in fairly small amounts, say as a garnish on miso soup, or fermented in forms like tempeh which render it somewhat safer. Not the gallons of soya milk, veggie burgers, tofu cheesecake etc that western vegetarians and processed food eaters consume.
It's much more sustainable to consume food which is produced close to your locality, and as organic as possible. There are even "ahimsa" forms of cow milk you can buy where the calf is left with the mother, which is the best thing to look out for if you can. Normal organic also has high welfare standards, will be fed on grass and the cowpats applied directly back to the soil to refertilise it, bypassing the need for industrial inputs.
If you do want to drink a vegan milk, oat would be your best bet... it's an established field crop here in Europe, requires less processing, transported much shorter distances and oats have some degree of health benefits.
With regard to sweeteners, cow milk naturally contains lactose, which breaks down to glucose and is the workaday fuel for your body. Whereas sweetened plant milks will contain sucrose or agave etc which contains high levels of fructose and is the form of sugar which is implicated in contemporary high levels of obesity, T2 diabetes, and other metabolic lifestyle diseases. Go for unsweetened if you can.
www.smallfootprintfamily.com/why-soy-is-bad-for-you-and-the-planet
www.i-sis.org.uk/argentinasRoundupHumanTragedy.php