Shovelware has certain traits because it wants to get your money so bad, and that makes it easy to avoid. There is the default shovelware UI look (skeumorphic and performative - not a lot of substance but very flashy, lots of emphasis on graphic design and little on content), the default shovelware sounds in trailers, and the default shovelware design ideas that come up again and again. These things are palatable to the vastest possible majority of people, so they are a sign of shovelware to be avoided.
Another sign of shovelware is that it tries to sell itself to you too much, or please you too much. Like a good people pleaser person, usually there are ulterior motives. This includes games that are way too easy and much too rewarding, fake trailers and key art that looks unreasonably good for a mobile game, use of IP-adjacent words (Great Mafia Auto: Miami) and so on.
In contrast, games I like will have complexity and it will usually be clear from their key art and trailers that losing is very possible, and some mastery is expected. For example, Zachtronics Soilitaire, Mini Motorways, Osmos, Elevate, and so on. Looping back to the first paragraph, these games also have UX and game design that is very different from the shovelware bunch.
I pick PC games the same way - if they are very heavily advertised but it's the same formula that has been done a million times and they don't offer much on top, I'll pass it. And if it's too hand-holding, I will pass it, too. There are games that are made to be extremely easy to consume and sweet on their players, and nothing else. Where all the game design (or incremental game design since the last release in the franchise) went to make it appeal to people more and not to offer anything new.
Games can be like refined sugar - very sweet when you eat it and triggering strong cravings when you're about to buy it; but after you've eaten it, you realize you've consumed trash. Nowadays, I like the games that have little bit more to them than just excessive player-pleasing (player service) as a form of extracting money at the fastest rate possible from as many people as remotely feasible.
So how do you find high quality games? Don't buy what's begging to be bought. Buy what's good on game design terms.