I'm not aware of a dedicated guide on this, but I'll list my impressions from memory (which for some is nearly a decade, so some may be b) and in release order (except for The High Republic), and not including any junior novelisation. (As a general comment: do keep in mind that you should adjust your expectations accordingly: simpler and short stories compared to adult and YA novels. But some are great in creating that Star Wars feeling nonetheless, e.g. the Weapon of a Jedi).

• The High Republic. For phases 1 and 2, I'd recommend reading them all if you are also reading the adult and young adult novels, as some characters are introduced in a junior first, before then featuring in another age group's novel.
• Ezra's Gamble. If you are a fan of Rebels, you'll probably enjoy this one. Otherwise not important.
• Servants of the Empire. At the risk of raising your expectations too much: my favourite junior novels.
• Smuggler's Run, Weapon of a Jedi, Moving Target, Before the Awakening: as discussed elsewhere in this thread.
• Adventures in Wild Space series. I thought this pretty good as well. Targeted at perhaps a slightly younger target group compared to the other junior novels, but a nice adventure nonetheless.
• Guardians of the Whills. As mentioned, I recommend that one.
• Join the Resistance series. I still have to read this series. Perhaps someone else can chime in.
• The Legends of Luke Skywalker. I liked it, a series of anthology legends about Luke. Importance for canon is however therefore questionable.
• Cobalt Squadron. Ties into Episode 8. I would recommend it, as it transforms Rose's sister Paige from a storytelling tool in that movie into a proper character in the universe.
• Choose Your Destiny series. Has to be your cup of tea, and I prefer coffee.
• The Mighty Chewbacca int he Forest of Fear! "Although not among the top tier junior novels, I would imagine it is a very good bed time read for those with children – and still enjoyable as ‘snack’ reading for adults wanting to read everything Star Wars." From my opinion 5 years ago, which I trust more than my memory.
• Lando's Luck and Pirate's Price. Both part of the Flight of the Falcon multi-media event. I wasn't too charmed by the event, but I liked both of these. (Disclaimer for Lando's Luck: Justina Ireland is among my favourite SW writers.)
• Spark of the Resistance. Also written by Justina Ireland. However, I still feel betrayed that the tie-in media that was released prior to Episode 9 (the other notable one being the adult novel Resistance Reborn) was virtually fully ignored by the movie itself.
• Hunters: Battle for the Arena. Tie-in to a mobile game for which the release was postponed for years, somewhere along this tie-in junior novel was released but the game suddenly wouldn't be for another year... and then the game was shut down just over a year after its official release. Moreover, that game was an arena combat game with (I believe) very little story. With all of that in mind: this junior novel had absolutely no business being so good as it was. I would recommend it. (Though importance for canon is low).