I tend to be highly paid, so I average about 1 job per 100 job applications. I typically try to craft each CV to each job needs, at least a little.
I've seen LinkedIn work, but only for double hitters: people who are well connected *and* the top 10% of their jobs.
I like to think I'm the latter, but not the former, so it's never worked for me.
It's a cliche, but the keys to employment is luck, flexibility, persistence, and never stop learning new skills.
A lesson I've learned after some decades is the following: Even though it's hard but be graceful when you don't get a job, I found I few kinds words to a recruitment agent in the final conversation sometimes pay dividends later.
As usual, don't quit your current job until you done a thorough Google search of the company. I usually look for articles of incorporation to see if they have aliases, how long they've been around,to see if they're based in an office, or out of someone's home. It's always worth trying to visit the office unannounced and anonymously to hopefully see the workspace beforehand, even if it just means sticking your head out of an elevator briefly.
Best of luck