John, and Charles Wesley were greatly influenced by Law
This is exactly why I never read William Law -- I read he was strongly influential on Wesley (and I believe mystical Wesleyan Arminian AW Tozer) and Wesley's and Tozer's theology turned out so bad, that's not saying much about the influencer. Plus Law being Church of England (against the Calvinistic Puritans) and Arminian -- definitely a no-go.
From experience, I've come to believe most non-fiction books (maybe 95%) are basically false -- completely fictional historical narratives, false theology, false political agendas, false worldviews, bad fake "science" or "stats" or "fake experts". So when I pick up a new book, the assumption is that it is trash or highly biased (everyone has an agenda!) and needs to be very carefully discerned. Thus, a new book or unfamiliar author is not something/someone to be trusted and devoured. With 95% odds the book is false, I discern every claim and look for a "proofnote" = footnote." I have come across SOOO many published books that made a claim but actually gave no footnote (proof) or provided a false footnote (didn't actually say what the author claimed).
If it helps, I've have had success discerning authors by drawing connections between theology and denominations, recommendations, influences etc. I always look up the denomination. 95% of the time, that says all we need to know. People go to the denomination that backs their theology. So if you know the ~15 most trustworthy Reformed denominations (RPCNA, PCA, URC, OPC, ARP, PRC, PRCA, RCUS, HRC, FRCNA, FPCS, FCC, RPCGA, AFC, KAPC etc), you can screen out all the bad authors easily into Roman Catholic, Arminian, etc. You will also know which version of Reformed theology you are being taught (there are strands that are passed down that follow a certain unique interpretation). If I'm reading a Scottish Reformed guy, he's probably teaching some version of the Marrowmen's unique theology going back to ~1645-1730s.
If no denomination, I look up the author and try to gather his theological/worldview/political beliefs. If he's Arminian, I'll skip him unless I'm reading to evaluate/critique -- then I pray to God for discernment first because many "a wise man" have read a Roman Catholic or an Arminian and slid right down into it and been lose. You can also discern authors/pastors by the seminary they went to. Or who his influencers were. Who he quotes in the book. You can tell AW Tozer is going to lead you astray because he's always quoting Roman Catholic mystics! So basically, when you read Tozer, you're reading Rome filtered through an Arminian mystic. Yipes!
Hope this helps your future reading!