Port Selection On The Newer Macs

There were no Late 2014 MacBook Airs. Assuming you are talking about Early 2014 models, they had

• One Thunderbolt 1 port that doubled as a Mini DisplayPort
• The ability to drive one Mini DisplayPort display, or two Thunderbolt ones, with resolution up to 2560x1600
• Two USB-A (USB 3.0) ports
• One MagSafe 2 port
• One 3.5mm headphone jack
• A SDXC card reader on the 13" model, but not on the 11" model

The M1 MacBook Airs have

• Two USB4 (USB 3.1 Gen 2, USB4, DisplayPort, Thunderbolt 3) ports
• The ability to drive one external USB-C or Thunderbolt display, with resolutions up to 6016x3384 pixels
• One 3.5mm headphone jack with support for high-impedance headphones
• No SDXC card reader

The M1 MacBook Air is missing a MagSafe charging port. (That came back with the M2 MacBook Airs, which have MagSafe 3.) It doesn't have a built-in SDXC card reader. But

• It can drive the same number of DisplayPort displays (one) as your old Air.
• It can drive monitors at higher resolutions than your old Air can.
• It offers faster maximum USB and Thunderbolt speeds.
• You can get very small, portable SDXC card readers that are about the size of USB thumb drives.
• There are many options for adapters, including inline USB-A to USB-C plug adapters, and display cables which go directly from USB-C (DisplayPort) to DisplayPort, Mini DIsplayPort, HDMI, or single-link DVI (so you are only dealing with a single cable; just a different one).

Here's an example of a portable SDXC reader that has USB-C and USB-A plugs, and offers USB 3.0 speed. (This isn't a USB-C to USB-A adapter, but a device that can be plugged into one or the other socket, as convenient.)

https://www.amazon.com/Vanja-Reader-Adapter-RS-MMC-Windows/dp/B07MBD66GZ

Why questions cannot be answered here as they are the domain of Apple programers, developers, R&D teams and etc. And Tim Cook.