With USB-C hubs for MacBooks, it really pays off not to go for the cheapest options. From my experience: I picked one up a couple months ago to finally be able to connect my MacBook properly, and I ran into a few things that matter. All those no-name Amazon parts aren't properly certified most of the time and don't deliver enough power for your MacBook. You'll notice it when the thing gets slower while charging or the connections keep dropping.
What actually works: check out the more established brands like Anker, Belkin, or Satechi. Yeah, they cost a bit more, but you've got the assurance that they'll last at least a year or longer. For me it turned out that hubs with well-made connectors are way more durable - if you're plugging stuff in and out constantly, that becomes a real problem with cheap ones. Make sure the hub properly supports Thunderbolt 3 / USB-C Power Delivery, otherwise your Air charges super slowly when you're on the go.
For what you need (HDMI, USB-A, SD reader), you need a pretty full-featured hub anyway, not just some cheap version. Before you buy, I'd filter the reviews to the last 3-6 months and see what problems people are actually running into - Amazon reviews are often older and sometimes manufacturers have changed their supply chain in the meantime. And not running too many ports at once is also a trick a lot of people don't know about: if you run everything simultaneously (HDMI + charging + external drive), even a good hub can struggle.