First point: Always remember Lenovo is owned by the chinese government and controlled with an iron fist.
This "tips" app may be doing a lot more shady crap than just pushing adverts.
Secondly, you need to report this to the ASA to start with. Pushing adverts WITHOUT clearing marking them as such is a major violation of UK advertising law.
Lenovo despite "not doing any harm" will have violated these laws many many tens or hundreds of thousands of times. And each advert carries large fines.
Lets make "tips" so unprofitable that Lenovo gives it up.
Also remember to post this stuff to Reddit, anywhere that sells lenovo equipment etc. If not, this practice 100% will expand to their range of PCs (which come already equipped with enough malware to download whatever they want).