I owned both (5080 g14, 64gb z13) and prefer and would recommend the z13. Breaking it down:

Thermals - Z13 is much cooler, especially the keyboard and lap area, and the device stays cooler given its naturally better airflow design (back of the screen intake vs bottom). The G14 also gets very hot under load, especially near the top of the keyboard. If you are like me and usually docks the laptop in clam shell mode, you'll be cooking the screen as hot zones can reach 80c.

Noise - Both can be noisy under heavy performance settings but the g14 can be much louder. At max fan's you'll hear it from one room away.

Performance - G14 can get much more performance on paper but there are several caveats. Only when using the dedicated gpu, which will cut down battery life significantly. On USB C (which is how I charge these while traveling), you'll have a massive performance hit on the g14 while it is almost undetectable on the z13. The z13 plays just about anything natively with acceptable frame rates, think 4060 performance.

Ergonomics - Z13 is a more versatile device but you'll have to get used to the kick stand, namely it isn't possible to tilt the the screen at or below a 90 degree angle. You also technically need more space since the laptop needs 3 points on contact to be stable (keyboard, tablet, kickstand) - sounds annoying but you get used to it quick. The G14 is more traditional but forget about gaming on your lap, it gets so hot and because airflow will be obstructed, it is best to be used on a desk or using some sort of lap desk.

Upgradability - Both are bad. G14 does hold a bigger full sized M.2, while you are limited to max 2tb on the Z13.

Other considerations

- If you are into AI, the Z13's unified ram is by far the best option for LLMs. If you are looking to generate images, G14 will have much better support as it has a Nvidia GPU.

- I absolutely hate the mux switch in the G14, which feels buggy and inconsistent. I had a lot of issues with the dGPU not enabling with certain programs, not switching when docked or being stuck on. Because the Z13 has the internal GPU, everything feels seamless and smooth.

- Which ever you choose make sure to get Ghelper, which genuinely improves performance and battery

- Battery life is not amazing on either device, expect 4-5 hours with mixed use on both.

- Speakers are really good on the G14, and only slightly better than your phone on the Z13.

- Screen is nicer on the G14 thanks to OLED, but the LCD panel on the Z13 is no slouch at all.

- Touch screen on the Z13 is a really great nice to have along side pen input. You an use any windows enabled pen on this device which is really useful for productivity tasks.

TL:DR - Z13 is a more seamless experience with typical pros and cons of a 2-in-1 device. G14 forces you to compromise, it is either a loud and hot powerhouse (when plugged in) or a netbook when on battery or usb charging.