Hi, you need to set your design rules to what your PCB manufacturer can provide, in this case, JLCPCB.
https://jlcpcb.com/capabilities/Capabilities
Here you can see that they definitely can handle this size BGA pads. 0.5mm > 0.4mm

You can also set your via size to smaller if you need any inner pads routed.

Also, I really hope that isn't autorouted and you won't use the autorouter, because that will potentially lead you to a non working device. PCB design can have many iterations so take the time to do it right. In the datasheet there is a layout example, please follow that and keep the components close, currently they are far apart for no reason. Try to have component placement and rotations that make the easiest and shortest trace routing available. C5 seems to be a part of the TMEM, the voltage on the TMEM pin depends on capturing the energy from
the digital ping from the transmitter and storing it on the C5 capacitor, which is waaaaay too far away from the IC, adds inductance and other unneeded factors there.

And vias in pads should not be used unless you absolutely need them, which you don't need here. That can lead to unreliable soldering as the via can suck the solder in the via and leave a questionable connection.
Here are some application notes from TI which you should check out.

Test and Troubleshoot a Wireless Power Receiver:
https://www.ti.com/lit/an/slua724/slua724.pdf?ts=1638167549518&ref_url=https%3A%2F%2Fwww.ti.com%2Fproduct%2FBQ51020



bq51020EVM (5-W WPC) Integrated Wireless Receiver
Power Supply:
https://www.ti.com/lit/ug/sluub03/sluub03.pdf?ts=1638167555856&ref_url=https%3A%2F%2Fwww.ti.com%2Fproduct%2FBQ51020



Layout Guidelines for Wireless Power Receiver:
https://www.ti.com/lit/an/slua710/slua710.pdf?ts=1638167556377&ref_url=https%3A%2F%2Fwww.ti.com%2Fproduct%2FBQ51020



Otherwise, good luck with the project! Hope it works out!

@deskpro256
Hey thanks a lot for these insights! And Yes, I did use auto route at the end, but I carefully placed all the components beforehand and routed the most important parts myself. I won't do that this second iteration! I'll switch the design rule capabilities like you said and I'll get rid of most the vias in pads as well as move in C5! As I definitely don't want any issues there.

This is honestly my first BGA and only my 3rd PCB design ever so I'm still very new at this all. I'd really appreciate hearing any more suggestions you have for ways to improve! And I'm definitely taking my time. This is a work in progress haha ;)

@tre.sellers3,

You must always read the datasheets for devices and follow their advice on things like power supply decoupling and PCB layout.

That sort of information is in the datasheet for good reasons.

:)

@andyfierman
Thanks for the advice! I have been trying my best to do so.