If you upgrade to a 3000 series APU plus install a separate GPU card it is possible under heavy loads your PSU might not be able to supply enough power to the GPU card. For normal computing like surfing the Net it is probably adequate.
With the APU you now have and a GTX 1050Ti according to this website (http://www.realhardtechx.com/index_archivos/Page362.htm) that recommends the minimum PSU wattage for various GPU cards it needs a PSU of 320 Watts.
Anyways before upgrading the PSU see if you have any Power symptoms when running your GPU or APU under heavy loads or stress.
EDIT: If you noticed there are no PSU less than 300 Watts in that extensive list for various GPU Cards in the link I provided.
I have had the GTX 1050ti graphics card installed and 32 GB ram everything seems to work ok.
My conclusion is, Lenovo supply computers with a 75w GPU and a 65w CPU and a 210w power supply. The GPU and CPU equal 140W this leaves 70w to supply everything else. For this computer Lenovo must think this is adequate.
On the other hand GPU manufacturers have to allow for different specs of computers, for example someone with a Ryzen 7 3800xt uses 105w for the CPU so with the GPU and CPU this equals 180w and some computers have bigger and more fans consuming more power. GPU manufacturers have to account for all situations and be cautious when recommending things.
This is just my theory, so for my computer I am happy for the upgrade but I will be keeping an eye on how my computer performs.